Robert spring 2012 Opus
(MODIFY OR REMOVE) OPTIONAL SUBTITLE
Hi my name is Robert i enjoy the outdoors very much. My future plans are to further my education at RIT and obtain a bachelors degree in software engineering.
On january 25 I experienced compressing and uncompressing files using gzip and gunzip. Gzip and gunzip are utilities you can use to allow for easy compressing of files and extracting of files. First gzip is used for compressing files. This utility works by opening up a command prompt and typing gzip(space)filesname.txt then press enter. This just compressed your file. To check to see if it is compressed type ls command on a command prompt and you will see filename.txt.“gz” meaning it was compressed with gzip utility. Now to unzip the compressed file type gunzip filename.txt and it will uncompressed to the current directory you are in. To check this issue ls command and see that your file does not have .gz after it. This is one way of easy compression and extracting files which is very useful utility to know.
chmod is a utility that allows you to change permissions on a file. My reason for writing about this utility is because changing permissions via the symbolic way is messy. When using chmod to change the permission you first need to understand a few things. First there are different permissions and they are: User (u) the user that owns the file, group (g) which is the group that owns the file and then other (o) which is everyone else on the system. Each of these has the read ® write (w) and execute/search(x) permission attached to each. An example would be rwxr-xr-x to rmatsch the answer.txt file. The first three letters correspond to the permission of the owner of the file then the next three are the permissions for group and then three more for other. Notice how there is a dash where a letter would be. This is because that particular group, owner,or other does not have that privilege. Also access to rwx for owner means access of (7). r-x means group access (5) and –x means other has access (1). This calculation is done by attributing the value 4 for read, 2 for write, and 1 for execute/search. If you add rwx you get (7). I should also mention the reason for 0-7 is because this is assigning of permissions by octal. For example, to assign read/ write/ execute permission for owner, read/execute for group and execute for other or commonly known as the “world” you would type in at the command prompt chmod 751 the answer.txt which would change the permission to the example listed above. The significant using octal for changing permission of files is because it takes longer changing files via symbolic notation, saving time and in the business world money. Changing permission via symbolic example: “Chmod o+rwx filename.txt” just sets other(o) to full permission read write and execute. A simple command such as “chmod 644 filename.txt” sets all three very quickly and less error is likly while typing.
root
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home
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rmatsch
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bin src file.c lab2 hello.c
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cprog unix submit
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Contact.info var2.c array.c
To access unconventional names there is three basic things to remember. When looking up files named unconventionally is not very fun thankfully you can use three characters to help with this. the characters are *,\, and ” ”. if given the file *?? ghty.file normal cat utility would when run on this would cat *?? And then cat ghty.file separately but if you were to type cat *??* you would be able to access the content. Another way use the \ to escape the following character so you would type cat *??\(space)ghty.file and then hit enter. Finally another quick and easy way is to use ” ”. This looks like this cat “*?? ghty.file” and then you can access the content.
* \ ” ” or ' '
Standard I/O (STDIO, STDOUT, STDERR)
■ Header Files (Local and System), C Standard Library (Libc), Libraries……X
■ arithmetic (equations, operators)…..X
■ logic and operators (and, or, not, xor)
■ Variables (types, ranges, sizes)…..X
■ Scope (Block, Local, Global, File)
■ Pointers (address of, assignment, dereferencing)…..X
■ Type Casting
■ Selection Structures (if, case/switch)……X
■ Repetition/Iteration Structures (for, while, do while)….X
■ Arrays (standard notation, pointer arithmetic, single-dimensional, multi-dimensional)…..X
■ File Access (Read, Write, Append)…..X
■ Structures (Declaration, Accessing Elements, Pointers to)
■ typedef, enum, union
■ Functions, Parameters (Pass by: Value, Address, Reference), Return Types, Recursion, Command-line arguments
■ Compiler, Preprocessor, Flags, Assembler, Linker, Multi-file programs (how to structure, how to compile)
■ I/O Streams (cin, cout, cerr, stream operators) [C++]
■ Namespaces [C++]
■ Type Casting Operators, Const-Volatility Specifiers (const, volatile) [C++]
■ Classes (Objects, Constructor, Destructor, Access Control, Public, Protected, Private, Friend, “this” pointer) [C++]
■ Inheritance (single, multiple Inheritance), Polymorphism/Virtual Functions, Abstract Base Class [C++]
■ Overloading (Functions, Operators) [C++]
■ Exception Handing (throw, try, catch) [C++]
■ Templates, STL (Standard Template Library) [C++]
Variables are storage containers which can be permanent but most of the time they vary or change throught a computer program.
Variables have 3 basic properties.First is name, in order to use a variable you must have declare a name for the variable to call it by. secondly you must select a data type such as type “interger” or “char”. Thirdly is the size of this container you want the variable to be. Thankfully this is already determined by the data type you have established so the work is already done. The data type selected can hold a certain amount of data. Below is code for a program to show you the different sizes of a data types there ranges the unique values they can have.I must also mention that upon selection of a data type there are signed and unsigned variables also. Signed variables can handle negative along with positive values and unsigned variables can handle only positive values.
Code :
#include <stdio.h> #include <math.h> int main() { // declare variables unsigned char uc = 0; signed char sc = 0; signed short int ssi = 0; unsigned short int usi =0; signed long int sli = 0; unsigned long int uli =0; signed long long int slli = 0; unsigned long long int ulli = 0; signed int si = 0; unsigned int ui = 0; unsigned long long int quantity = 0; //display info for unsigned char data type printf("Unsigned char is %u bytes\n", sizeof(uc)); printf("The range of an unsigned char is %hhu to %hhu\n", uc, (uc-1)); quantity=(unsigned char)(uc-1) + 1;/* unsigned char -1 = 255 +1 for all unique values*/ printf("An unsigned char can store %llu unique values\n\n", quantity); //display info for signed char data type printf("Signed char is %d bytes\n", sizeof(sc)); quantity = (unsigned long long int)pow(2, (sizeof(sc)*8)); /*2 raised to the power of 8 times data type in bytes */ printf("The range of a signed char is %hhd to %hhd\n", (sc-(quantity/2)), (sc+(quantity/2)-1)); printf("A unsigned char can store %llu unique values\n\n", quantity); printf("Unsigned short int is %u bytes\n", sizeof(usi)); quantity = (unsigned long long int)pow(2, (sizeof(usi)*8)); printf("The range of a unsigned short int is %u to %llu\n", usi, ((quantity)-1)); printf("An unsigned short int can store %llu unique values\n\n", quantity); printf("Signed short int is %d bytes\n", sizeof(ssi)); quantity = (unsigned long long int)pow(2, (sizeof(ssi)*8)); printf("The range of a signed short int is %lld to %lld\n", (ssi-(quantity/2)), (ssi+(quantity/2)-1)); printf("A signed short int can store %llu unique values\n\n", quantity); printf("Signed int is %d bytes\n", sizeof(si)); quantity = (unsigned long long int)pow(2, (sizeof(si)*8)); printf("The range of a signed int is %lld to %lld\n", (si-(quantity/2)), (si+(quantity/2)-1)); printf("A signed int can store %llu unique values\n\n", quantity); printf("Unsigned int is %u bytes\n", sizeof(ui)); quantity = (unsigned long long int)pow(2, (sizeof(ui)*8)); printf("The range of a unsigned int is %llu to %llu\n", ui,((quantity)-1)); printf("An unsigned int can store %llu unique values\n\n", quantity); printf("Signed long int is %d bytes\n", sizeof(sli)); quantity = (unsigned long long int)pow(2, (sizeof(sli)*8)); printf("The range of a signed long int is %lld to %lld\n", (sli-(quantity/2)), (sli+(quantity/2)-1)); printf("A signed long int can store %llu unique values\n\n", quantity); printf("Unsigned long int is %u bytes\n", sizeof(uli)); quantity = (unsigned long long int)pow(2, (sizeof(uli)*8)); printf("The range of a unsigned long long int is %llu to %llu\n", uli,((quantity)-1)); printf("An unsigned long int can store %llu unique values\n\n", quantity); printf("Signed long long int is %d bytes\n", sizeof(slli)); quantity = (unsigned long long int)pow(2, (sizeof(slli)*8)); printf("The range of a signed long long int is %lld to %lld\n", (slli-(quantity/2)), (slli+(quantity/2)-1)); printf("A signed long long int can store %llu unique values\n\n", quantity); printf("Unsigned long long int is %u bytes\n", sizeof(ulli)); quantity = (unsigned long long int)pow(2, (sizeof(ulli)*8)); printf("The range of a unsigned long long int is %llu to %llu\n", ulli,((quantity)-1)); printf("An unsigned long long int can store %llu unique values\n\n", quantity); return(0); }
What command line looks like when program is run.
lab46:~/src/cprog$ ./project0 Unsigned char is 1 bytes The range of an unsigned char is 0 to 255 An unsigned char can store 256 unique values Signed char is 1 bytes The range of a signed char is -128 to 127 A unsigned char can store 256 unique values Unsigned short int is 2 bytes The range of a unsigned short int is 0 to 65535 An unsigned short int can store 65536 unique values Signed short int is 2 bytes The range of a signed short int is -32768 to 32767 A signed short int can store 65536 unique values Signed int is 4 bytes The range of a signed int is -2147483648 to 2147483647 A signed int can store 4294967296 unique values Unsigned int is 4 bytes The range of a unsigned int is 0 to 4294967295 An unsigned int can store 4294967296 unique values Signed long int is 8 bytes The range of a signed long int is -9223372036854775807 to 9223372036854775806 A signed long int can store 18446744073709551615 unique values Unsigned long int is 8 bytes The range of a unsigned long long int is 0 to 18446744073709551614 An unsigned long int can store 18446744073709551615 unique values Signed long long int is 8 bytes The range of a signed long long int is -9223372036854775807 to 9223372036854775806 A signed long long int can store 18446744073709551615 unique values Unsigned long long int is 8 bytes The range of a unsigned long long int is 0 to 18446744073709551614 An unsigned long long int can store 18446744073709551615 unique values
variables are seen as memory cells that can be accessed using their identifiers (aka pointers). Because we did not have to care about the physical location of our data within memory, we can simply used its identifier when we need to refer to the variable.
Below is code to help understand what pointers acually do.
#include <stdio.h> int main() { // a is initiallly set to zero int a = 0; int * b; /* b is declared as a pointer variable by star b */ b = &a; /* b is assigned the adress of a */ *b = 12; /* what ever b is pointing at is now set equal to 12 not b itself */ printf("a contains %u \n", a ); printf("a's address is 0x%x\n", &a ); printf("b contains %u \n", *b); // b contains the value stored at what b is pointing to. (the container or another variable) printf("b points to 0x%x\n", b); printf("b's addres is 0x%x\n", &b); return(0); }
lab46:~/src/cprog$ ./var2 a contains 12 a's address is 0xe5a3f33c b contains 12 b points to 0xe5a3f33c b's addres is 0xe5a3f330
+ Adding binary operator, adds two operands to get a sum, (addend +adend = sum - Subtract binary operator, inverse of adding, (minuend -subtrahend = difference) % Modulus takesremainder after an integer division ++ means +1 -- means -1 * Multiply binary operator (multiplicand times multiplier = product) / Divide binary operator(dividen / divisior = quotient)
c=5 b=3 p=5 q=5 c-b=a = 5-3=2 a =2 c+b=a = 5+3=8 a =8 c*b=a = 5*3=15 a =15 x=p/q = 5/5=1 a =1 c++ means c= to 5 plus one =6
Header files
Header Files are files that are incoporated in c code to allow you added funtionality such as use of funtions or expressions.
#include <stdio.h> #include <stdlib.h> code to demonstrate
#include <stdlib.h> #include <stdio.h> int main() { return(0); }
Arrays
Arrays can be thought of as sequentialy ordered containers. The ability to take a big piece of data such as string and break it up into individual pieces to be manipulted as needed. because arrays store data in “numbered containers” arrays are a good thing to know.
#include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { unsigned char i; if (argc<2) { printf("%8s must be run with 1 or \ more arguments, you only provide %hhu\n", *(argv+0),(argc-1)); exit(1); } printf("pleas enter a message to be ciphered") for(i=0;i<argc; i++) { printf("argv[%hhu]: %s \n",i,*(argv+i)); } return(0); }
./acs h e y t h i s i s a n a r r a y you ran this program with 17 arguments, they are: argv[0]: ./acs argv[1]: h argv[2]: e argv[3]: y argv[4]: t argv[5]: h argv[6]: i argv[7]: s argv[8]: i argv[9]: s argv[10]: a argv[11]: n argv[12]: a argv[13]: r argv[14]: r argv[15]: a argv[16]: y
multidemensional array would look similar to this
0 1 2 3 0 y r e d 1 a b h o 2 f k z p 3 t u m l argv[1][2]:k
Selection Structures (if, case/switch)
selection structure is a order of sequence of check statments (conditional statements) that are true or false. If the stament is true then do somthing.
if (in == NULL){ fputs("please enter a message to cipher:\n", stdout); fgets(msg, sizeof msg, stdin); fprintf(nf, "%s", msg); fclose(nf); nf = fopen("nofile.txt", "r"); letter1 = fscanf(nf,"%c", &letter); }else{ letter1 = fscanf(in, "%c", &letter); }if (key == NULL){ printf("please enter a key to encipher with :\n"); scanf("%d", &keyvalue); }else{ fscanf(key,"%d",&keyvalue);
Repetition/Iteration Structures (for, while, do while)
Repetitive/iteration structures or loops are a statement which allows code to be repeatedly executed until a condition is meet or can be instructed to “do” something while this condition is true.
#include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { unsigned char i; if (argc<2) { printf("%8s must be run with 1 or \ more arguments, you only provide %hhu\n", *(argv+0),(argc-1)); exit(1); } printf("you ran this program with %hhu arguments, they are:\n", argc); for(i=0;i<argc; i++)/* Condition to be checked */ { printf("argv[%hhu]: %s \n",i,*(argv+i)); } return(0); }
another example
while (letter1 != EOF)
{
if((letter >= 'A') && (letter <= 'Z'))
letter = (((abs(letter - 65) + keyvalue)%26)+65);
else if((letter >= 'a') && (letter <= 'z'))
letter = (((abs(letter - 97) + keyvalue)%26)+97);
fprintf(out,"%c",letter);
if (in == NULL){
letter1 = fscanf(nf, "%c", &letter);
}else{
letter1 = fscanf(in, "%c", &letter);
}
File access
File Access is when you read from, write to, or append to a file. the program can read write or append to a file.
Demonstration of the chosen keyword.
If you wish to aid your definition with a code sample, you can do so by using a wiki code block, an example follows:
#include <stdio.h> #include <stdlib.h> #include <math.h> int main(){ char letter1=0; char msg[250]; FILE *in, *out, *key,*nf; char letter = 0; int keyvalue; nf = fopen("nofile.txt", "w"); in = fopen("message.txt", "r"); out = fopen("cipher.txt", "w"); key = fopen("key.txt","r"); if (in == NULL){ fputs("please enter a message to cipher:\n", stdout); fgets(msg, sizeof msg, stdin); fprintf(nf, "%s", msg); fclose(nf); nf = fopen("nofile.txt", "r"); letter1 = fscanf(nf,"%c", &letter); }else{ letter1 = fscanf(in, "%c", &letter); }if (key == NULL){ printf("please enter a key to encipher with :\n"); scanf("%d", &keyvalue); }else{ fscanf(key,"%d",&keyvalue); } while (letter1 != EOF) { if((letter >= 'A') && (letter <= 'Z')) letter = (((abs(letter - 65) + keyvalue)%26)+65); else if((letter >= 'a') && (letter <= 'z')) letter = (((abs(letter - 97) + keyvalue)%26)+97); fprintf(out,"%c",letter); if (in == NULL){ letter1 = fscanf(nf, "%c", &letter); }else{ letter1 = fscanf(in, "%c", &letter); } }if (in == NULL){ fclose(nf); }else{ fclose(in); } if (key != NULL){ fclose(key); } //fclose(in) fclose(out); //fclose(nf); return(0); }
lab46:~/src/cprog$ cat cipher.txt jpa lab46:~/src/cprog$ lab46:~/src/cprog$ cat plain.txt hey lab46:~/src/cprog$
The course objective is for students to be able to write, compile code, use pointers and variables effectively and efficiently. Also this course is designed for students to gain a basic comprehension of memory such as various data types. Also obtain valuable debugging skills and demonstrate the ability to use logic and structure to solve problems. Develop solutions shown in c++ program language.
To measure successful academic/intellectual achievement of this objective. students should be given a final project that incorporates various lessons learned through the course because an important part of intellectual achievement is applying what you leaned. Students should also be asked to write various programs on the spot and should be completed given sufficient time.
Correctness - are things displayed when they are supposed to, were variables initialized etc. Design/efficiency- there is many ways to design a program but there may be better ways or more efficient ways. (Are the right size variables used?)
Logic- has a basic concept of logic (uses loop instead of 100 if statements) Other- Does the program do what it was designed to do and accurately.
Reflecting upon my results of the measurement to ascertain achievement of the course objective.
* How did you do? I did not do to bad but still have a lot to learn. * Is there room for improvement?yes * Could the measurement process be enhanced to be more effective? Yes * Do you think this enhancement would be efficient to employ? Yes * Could the course objective be altered to be more applicable? No
Reflecting on the measurements I did not do too bad, but of course have a lot to learn so there is much room for improvement.
Local host….X
■ Remote host……X
■ Home directory……X
■ Current working directory…..X
■ Types of files (regular, directory, special)……X
■ File manipulation…..X
■ Text Processing…..X
■ The VI editor…..X
Local host
Local host is is the standard hostname given to the address of the loopback network interface or the web address of the computer you are working on. Although local host can take different forms, the web address is simply your computer's identifier.
enter “http://127.0.0.1” into any web browser, and you will see a web page hosted by a web server on the same computer if one is running.
Remote host
Remote hosts are computers that are not locally accessed. They are further away from where you are such as servers or public internet.
a computer connected to lab46.corning-cc.edu through ssh is an example of a remote host
File Manipulation
file manipulation is the ability to control files such as moving them, removing them, copying them.
lab46:~/src/cprog lab46:~/src/cprog$ touch file123 lab46:~/src/cprog$ cp file123 file2 lab46:~/src/cprog$ rm file123 rm: remove regular empty file `file123'? y lab46:~/src/cprog$ mkdir file123 lab46:~/src/cprog$ rmdir file123 lab46:~/src/cprog$ mv file2 /tmp lab46:~/src/cprog$ lab46:~/src/cprog$ cd /tmp lab46:/tmp$ ls A.txt cformansencryption.c fishd.log.vcordes1 img--01315.htm img--93112.asc lost+found nofile.txt prog1x5 aptitude-rlott.11795:dKeQWo fbarb.txt fishd.socket.vcordes1 img--12835.htm img-file-88471.c mc-jbamper plain.txt prog1x5.c aptitude-rlott.11860:1ABldB file2 hsperfdata_brobbin4 img--39027.htm img-logout-04391.asc mc-tedmist1 prog1x4.c wierdfileiswierd lab46:/tmp$
Home directory
The home directory is your default directory. Whenever you open up a cmd prompt you are at your home directory.
root
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home
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rmatsch
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___________________________
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bin src file.c lab2 hello.c
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cprog unix submit
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Contact.info var2.c array.c
login as: rmatsch rmatsch@lab46.corning-cc.edu's password: __ _ _ _ __ . . . . . . . . . . . . . . . . . . . . . . . . . | | __ _| |__ / | |_/ / . Basic System Usage: Type 'usage' at prompt . | |__/ _` | '_ \\_ _/ _ \ . Events and News: Type 'news' at prompt . |_____\__,_|_.__/ |_|\___/ . Broken E-mail? Type 'fixmail' at prompt . --------------------------- . Check Lab46 Mail: Type 'alpine' at prompt . c o r n i n g - c c . e d u . . . . . . . . . . . . . . . . . . . . . . . . . Lab46 is the Computer & Information Science Department's Student Development Server for Computer-related coursework, projects, and exploration. For more information, please check out: .. . . . . . . . . . .. . Lab46 Web Page: http://lab46.corning-cc.edu/ . . Lab46 Help Form: http://lab46.corning-cc.edu/help_request . . Help E-mail: haas@corning-cc.edu or wedge@lab46.corning-cc.edu . .. . . . . . . . . . .. You have old mail. Last login: Sat Mar 3 09:06:57 2012 from user-10bj433.cable.mindspring.com lab46:~$
by typing pwd you are shown where you are at in relaton to directories. Also by typing in cd you are defaulted back to your home directory even if you are in another directory.
lab46:~$ lab46:~$ pwd /home/rmatsch lab46:~$ cd src lab46:~/src$ cd lab46:~$
Current working directory
The current working directory is the directory that you're in.
The current working directory is the directory that you are in. Typing cd command with no arguments will change your current working directory to your home directory.The pwd command reveals the current working directory.
lab46:~$ cd src/unix lab46:~/src/unix$ pwd /home/rmatsch/src/unix lab46:~/src/unix$ cd lab46:~$ pwd /home/rmatsch lab46:~$
Text Processing
Text Processing is a tool used to edit text, save text into files or from files but can also be used to change it other text files.
“nano” is a good example of a text processing.
lab46:~$ lab46:~$ nano hello.c
#include<stdio.h>
int main()
{
printf("Hello, World !\n");
return(0);
}
Types of files (regular, directory, special)
There are three basic types of files, regular files like text, directories such as a file that contains other files within, and special files which can be programs.
hello1.c is a txt file,unix is a directory that contains other files,and hello1 is a compiled c code program.
lab46:~/src$ ls Makefile cprog hello1 hello1.c submit unix lab46:~/src$ lab46:~/src$ cd unix lab46:~/src/unix$ lab46:~/src/unix$ ls arc.tar.gz cs1.txt cs3.txt cs5.txt lab1.txt lab3.txt lab5.txt contact.info cs2.txt cs4.txt lab0.txt lab2.txt lab4.txt shell lab46:~/src/unix$
Vi editor
The VI editor is a text editor with two modes one mode you can only insert, and in another mode you can only enter commands.
Demonstration of the chosen keyword.
lab46:~$ vim hello.c
#include<stdio.h>
int main()
{
printf("Hello, World !\n");
return(0);
}
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
"hello.c" 7L, 76C
to write to this file i must hit the i key for insert and then insert is diplayed to show you what mode you're in.
~ -- INSERT --
to save changes go to command mode by hitting esc key and then typing :wq to quit without saving type :q!
Upon completion of this course, students should be able to show:
familiarity with the structure of UNIX systems the ability to accomplish/automate tasks exposure to command-line tools and utilities experience the connection between UNIX and C understanding of the UNIX philosophy exposure to Open Source concepts and ideals familiarity with important system concepts exposure to computer security understanding and use of pattern matching problem solving activities
The objective entails being familiar and comfortable in using unix to accomplish task. It also entails understanding basic understandings of unix.
The method i use for measuring successful academic/intellectual achievement of this objective would be to be asked to complete various task to be completted in a timly mannor for a final.
Follow your method and obtain a measurement. Document the results here.
upon reflect my achievement of the particular course objective. i would do pretty good. Although i do pretty well there still could be room for improvement but am happy with the results.The measurement process could be enhanced to be more effective if more task were asked.I also believe these enhancement would be efficient to employ.however, what is asked for the objective is fine.
What happens when you initialize a variable before the loop instead of initializing within the loop condition?
When using a loop in a program you have a condition that must be checked for the loop to start and end the loop. Usually the loop counting variable is initialized in the check condition of the loop.(common programming practice of loops)
Before actually performing the experiment I believe that it will make no difference in how the program runs as long as the variable is not used before it is needed. Declaring global variables in a program are so you can use those variables throughout and at any part in the program so this includes the loop.
I am going to test my hypothesis by developing a program which has a loop counting variable except i will initialize the variable in the start of the program instead of within the loop condition. My experiment will begin by first making a small program with initialization done within the loop condition. Then testing to make sure the program works and there are no bugs. Then I can proceed to initialize before the loop and not initialize with in the loop to see what happens.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
unsigned char i;
i=0;
if (argc<2)
{
printf("%8s must be run with 1 or \
more arguments, you only provide %hhu\n", *(argv+0),(argc-1));
exit(1);
}
printf("you ran this program with %hhu arguments, they are:\n", argc);
for(i<argc; i++)
{
printf("argv[%hhu]: %s \n",i,*(argv+i));
}
return(0);
}
The out come of this exsperiment for the above code did not work out. Upon analysis of why i looked closer at the loop condition parameters.The loop condition wants three parameters. this is known because when you go to **manuel for the “for loop” or type “man 3 for” in command line and get this 'For' loop
“SYNOPSIS
for start test next body
_
DESCRIPTION
For is a looping command, similar in structure to the C for statement. The start, next, and body arguments must be Tcl command strings, and test is an
expression string. The for command first invokes the Tcl interpreter to execute start. Then it repeatedly evaluates test as an expression; if the result
is non-zero it invokes the Tcl interpreter on body, then invokes the Tcl interpreter on next, then repeats the loop. The command terminates when test eval-
uates to 0. If a continue command is invoked within body then any remaining commands in the current execution of body are skipped; processing continues by
invoking the Tcl interpreter on next, then evaluating test, and so on. If a break command is invoked within body or next, then the for command will return
immediately. The operation of break and continue are similar to the corresponding statements in C. For returns an empty string."
A loop condition will not look anywhere else in the program for the variables it needs. The loop expects the initialization to be done within the loop condition.(Example)for(i=0;i<argc; i++). The loop counter will not add outside of the loop and pull the info back to check it expects the variable to be initialized within the parentheses.so by my experiment i have proved my hypothesis to be incorrect and there was more involved then initially thought.
What will happend when i change *4 to *3 when allocating sizeof char when dealing with arrays.
class notes.
Based on what you've read with respect to my original posed question, i believe that in a program that is dependant on atleast 4 memory spaces when changed to 3 will cause a segmentation fault or possible incorrect results.my rayional for this is because when there is not eough space it will usually truncate but to low of memory i believ it will seg fault.
by running a program that depends on space for array and taking space out to see what will come of the program.
The prgram compiled but when running it segmentation faulted.
Based on the data collected:
What can you based on the experiment i can ascertain that by running a program with less memory then required will cause a segmentation fault.
What will happen if i use single quotes in a prinf funtion?
C ansi book
I believe you will obtain an err message when tyring to compile. the reason for my educated guess is because printf() usually prints whats is in double quotes.
my exsperiment will entail creating a program that prints a mesage to stdout with quotes and then without quotes
#include<stdio.h>
int main()
{
printf("Hello, World !\n");
return(0);
}
and the other code to run is:
#include<stdio.h>
int main()
{
printf('Hello, World !\n');
return(0);
}
lab46:~$ gcc -o hello hello.c hello.c:5:16: warning: character constant too long for its type hello.c: In function 'main': hello.c:5: warning: passing argument 1 of 'printf' makes pointer from integer without a cast /usr/include/stdio.h:339: note: expected 'const char * __restrict__' but argument is of type 'int' lab46:~$
Based on the data collected the code did compile so i was wrong but when running the program it segmentation faulted.
I was suprised it compiled at first but when giving the exsperiment more time to think i the reason for warning is because it was taking hello, world! and putting it into string so that explains warnings and segmentation fault.
For the UNIX course I currently enrolled in i have created a IRC bot phenny.It's pretty cool, once you get going it becomes alot of fun. Creating a phenny bot is significant because it allows you to script a bot and based on some conditions the bot does things.In the begining i had some difficulty with scripting but this activity helped me.
GNU debugger when you compile code use -g along with regular compile which looks like this gcc -g -o acs2 acs2.c
then run your program in the debugger:
gdb ./acs2 to fully use this debugger set breaking points such as break main break 11 break 17 once breaking points are set then you can run the program by typing “run” type “n” for next line you can also print values of variables if you type print “the variable name”
this is a very useful tool for finding possible mistakes or to fix mistakes. this is a very basic use of gnu debugger this debugger is capible of much more so please explore.
C++ OOP-Object-Oriented Programming to make a C++ file type .cc after you file instead of .c compile with g++ -o hello1 hello.cc
C++ class notes Classes & Objects Inheritance/Multiple Inheritance Polymorphism Templates
class notes on struct
struct person{
char *name;//or --char name[20];
unsigned char age;
short int weight;
float gpa;
};
//struct differ from union bec struct allocate memory for each and dont share $
typedef struct person P;
P p1,p2,p3,p4,p5;
struct person p1;
struct person p2;
struct person p3,p4,p5;
p1.age = 29;
Standard I/O (STDIO, STDOUT, STDERR)…xxxx ■ logic and operators (and, or, not, xor)
■ Scope (Block, Local, Global, File)
■ Type Casting
■ Structures (Declaration, Accessing Elements, Pointers to)
■ typedef, enum, union
■ Functions, Parameters (Pass by: Value, Address, Reference), Return Types, Recursion, Command-line arguments
■ Compiler, Preprocessor, Flags, Assembler, Linker, Multi-file programs (how to structure, how to compile)……x
■ I/O Streams (cin, cout, cerr, stream operators) [C++]……xxx
■ Namespaces [C++]…xxx
■ Type Casting Operators, Const-Volatility Specifiers (const, volatile) [C++]
■ Classes (Objects, Constructor, Destructor, Access Control, Public, Protected, Private, Friend, “this” pointer) [C++]…..xxxxx
■ Inheritance (single, multiple Inheritance), Polymorphism/Virtual Functions, Abstract Base Class [C++]
■ Overloading (Functions, Operators) [C++]
■ Exception Handing (throw, try, catch) [C++]
■ Templates, STL (Standard Template Library) [C++]
Flags In programming, a flag is a predefined bit or bit sequence that holds a binary value. Typically, a program uses a flag to know when a data stream ends and new data begins. good example is flags used in networking. For example: 1010100 (flag to say hey begin recording) 0101101 (data) 0111011 (data) 0101011(flag to say hey end of data stream)
assembler Is a program that takes basic text in a programing laguage and translates it into bits the processor uses for excution of task. is you are engineer that builds computers you would most likly know assembly laguage.
Binary Code code made of 0's and 1's known as low level programming, called machine language that most programmers don't work with but compiler use.(Assembly language)
Preprocessor program started by the compiler as the first part of translation,it handles #include, #define, and #if.by replaceing #include with stdlib.h or other hearder files you have listed example #include <stdlib.h>
I/O Streams (cin, cout, cerr, stream operators) [C++]
in c you use stdin, stdout, and stderr. in C++ you use cin, cout, and cerr. cout- is an object of class that represents the standard output stream. cin- Standard input stream (object) cerr- Standard output stream for errors (object)
<iostream> in C++ example while (true) {
cout << "Please enter a valid number: "; getline(cin, input);
in c int value =0; printf(“please enter a number:\n”); fscanf(stdin,%d,&value);
c++ is a way to maintain your code through c lasses to make code more organized. in this class there is there is a public,private protected. these are the access for the class. what is in public can be accessed from anyone. thoses in private cannot be accessed at all from anyone unless there is a way to access it in protected like in the below example with get x.
#ifndef _GATE_H #define _GATE_H //sample code for classes dealing with inheritance //abstract base class.. //base class class gate{ public: gate(); // constructor bool getx(); void seta(bool); void setb(bool); protected: void setx(bool); bool a; bool b; private: bool x; }; #endif
When using same type of data for many declarations, you can customize its name and “re use it with out re writing the name again and again . In C++, the type def keyword allows you to create an alias for a data type. The formula to follow is: typedef [attributes] DataType AliasName; The typedef keyword is required. The attribute is not.
Enum short for enumerated data allow a user to define a fixed set of words that a variable of type enum can use as its value. The words are assigned integer values by the compiler so enum values can be compared.
A union is comprised of a collection of variables of different types, just like a structure. However, with unions, you can only store information in one field at a time. Once a new value is assigned to a field, any existing data is overwritten with new data. The use of unions can save memory if you have a grouping of data and only one of the types is used at a time. The size of a union is dependent on the size of it's largest data member.
struct person{
char *name;//or --char name[20];
unsigned char age;
short int weight;
float gpa;
};
//struct differ from union bec struct allocate memory for each and dont share like union
typedef struct person P;
P p1,p2,p3,p4,p5;
struct person p1;
struct person p2;
struct person p3,p4,p5;
p1.age = 29;
stdio or standard input is defaulted to the the keyboard. standard output is defaulted to the screen. stderr is also defaulted to the screen for err msgs
is a thing that is inherited. example: B can inherit A and be a child
Demonstration of the chosen keyword.
gate :: gate() {
a=b=x=false;
} bool gate :: getx() {
return(x); //return x to have acces to x
}
void gate :: seta(bool a) {
this->a=a; //property of c++ refer to self
} void gate :: setb(bool b) {
this->b=b;//-> this is a pointer
} void gate :: setx(bool x) {
this->x=x;
}
Namespaces allow to group like classes, objects and functions under a name.
namespace myNamespace {
int a, b;
}
A function in the C programming language is code that has a name and property that are reusable. This means that a function can be called on from as many different points in the program as needed.
A Parameter in the C programming language is any data that is passed to a function. Demonstration
#include<stdio.h>
#include<stdlib.h>
int sum(int, int, int, int); //function and parameters expected
float avg(int, int, int, int); //function and parameters expected
int main(int n1)//main is accepting a integer value for parameter
{
return(0);
}
establish a better understanding of c and c++
the objective entails learning about type defs classes and working projects
create a program that incorporates classes with code and type defs
upon Reflection of my results of the measurement to ascertain your achievement of the particular course objective.
■ $PATH….X
■ Job control…….x
■ wildcards……x
■ tab completion…..x
■ Cron/Crontab…….x
■ Pattern Matching………x
■ Regular Expressions…….x
■ Shell Scripting…..x
shell scripting
shell scripting is a small program essentialy that contains commands such as command line task such as grep, ls, mv, and cp. when you run the script it it excute these for you instead of typing all theses things.
ls ~ df who
is in script.sh
lab46:~$ ./script.sh Desktop archive2.zip count.c mail Documents archives data motd Downloads archivescombined.tar date multitask.lab.txt Maildir at dateyears output Music badname devel phenny Pictures badname.tgz file phenny.tar.bz2 Public bin forloop.sh script.sh Templates botscript.sh guess1.sh src Videos class_notes lab1 src.bak age.sh classlog.c lab2 the answer.txt archive1.tar.gz count loop.sh Filesystem 1K-blocks Used Available Use% Mounted on /dev/xvda1 4128448 2522072 1396664 65% / tmpfs 784300 0 784300 0% /lib/init/rw udev 755640 36 755604 1% /dev tmpfs 784300 4 784296 1% /dev/shm /dev/xvda2 253871 12859 227905 6% /tmp nfs:/home 2930056576 1434124544 1495932032 49% /home nfs:/lib/mail 2930056576 1434124544 1495932032 49% /var/mail skinney1 pts/8 2012-03-17 11:36 (cpe-24-94-52-91.stny.res.rr.com) rmatsch pts/16 2012-03-17 11:46 (user-10bj433.cable.mindspring.com) jjohns43 pts/24 2012-01-23 12:18 (cpe-74-65-82-173:S.0) smalik2 pts/29 2012-03-17 10:49 (cpe-69-205-204-88.stny.res.rr.com) skinney1 pts/35 2012-03-16 10:15 (65-124-85-125.dia.static.qwest.net) mfaucet2 pts/65 2012-03-09 17:09 (55:S.0) smalik2 pts/27 2012-01-25 14:53 (cpe-69-205-204-88:S.0) wedge pts/28 2012-03-17 10:02 (telstar.lair.lan) jdavis34 pts/22 2012-03-06 12:57 (cpe-69-205-141-69:S.0) jjohns43 pts/82 2012-02-27 11:03 (cpe-74-65-82-173:S.0) lab46:~$
PATH is an environmental variable that specifies a set of directories where executable programs are located.
lab46:~$export PATH=$PATH:/home/rmatsch/src/unix
Job control allow you to have the system work on a job in the background while you do something else . If you are simply trying to get logged out, but have encountered the “There are stopped jobs” message
Useful Commands control-z Stop (don't kill) the foreground job, and then return to the shell
Check the status of jobs in the current session ps -u username Check the status of processes, including those from other sessions. On BSD systems, use 'ps -gx'. kill -9 %1 Kill a job, by specifying its job number after the percent sign kill -9 123 Kill a process, by specifying its process id (PID) number bg Run the most recently stopped job in the background fg Bring most recently background job to the foreground fg %1 Bring a job to foreground by specifying its job number after the percent sign
A daemon is a computer program that runs in the background as a process, instead of running in the foreground. below is an example of a deamon running in back ground and a command to look at the root processes.
inetd or init
lab46:~$ ps -u root USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0.0 0.0 8356 720 ? Ss Jan17 0:41 init [2] root 2 0.0 0.0 0 0 ? S Jan17 0:00 [kthreadd] root 3 0.0 0.0 0 0 ? S Jan17 0:05 [migration/0] root 4 0.0 0.0 0 0 ? S Jan17 0:08 [ksoftirqd/0] root 5 0.0 0.0 0 0 ? S Jan17 0:00 [watchdog/0] root 6 0.0 0.0 0 0 ? S Jan17 0:04 [migration/1] root 7 0.0 0.0 0 0 ? S Jan17 0:03 [ksoftirqd/1] root 8 0.0 0.0 0 0 ? S Jan17 0:00 [watchdog/1] root 9 0.0 0.0 0 0 ? S Jan17 5:40 [events/0] root 10 0.0 0.0 0 0 ? S Jan17 3:53 [events/1] root 11 0.0 0.0 0 0 ? S Jan17 0:00 [cpuset] root 12 0.0 0.0 0 0 ? S Jan17 0:00 [khelper] root 13 0.0 0.0 0 0 ? S Jan17 0:00 [netns] root 14 0.0 0.0 0 0 ? S Jan17 0:00 [async/mgr] root 15 0.0 0.0 0 0 ? S Jan17 0:00 [pm] root 16 0.0 0.0 0 0 ? S Jan17 0:00 [xenwatch] root 17 0.0 0.0 0 0 ? S Jan17 0:00 [xenbus] root 18 0.0 0.0 0 0 ? S Jan17 0:06 [sync_supers] root 19 0.0 0.0 0 0 ? S Jan17 0:07 [bdi-default] root 20 0.0 0.0 0 0 ? S Jan17 0:00 [kintegrityd/0] root 21 0.0 0.0 0 0 ? S Jan17 0:00 [kintegrityd/1] root 22 0.0 0.0 0 0 ? S Jan17 0:00 [kblockd/0] root 23 0.0 0.0 0 0 ? S Jan17 0:00 [kblockd/1] root 24 0.0 0.0 0 0 ? S Jan17 0:00 [kseriod] root 27 0.0 0.0 0 0 ? S Jan17 0:00 [kondemand/0] root 28 0.0 0.0 0 0 ? S Jan17 0:00 [kondemand/1] root 29 0.0 0.0 0 0 ? S Jan17 0:02 [khungtaskd] root 30 0.0 0.0 0 0 ? S Jan17 0:20 [kswapd0] root 31 0.0 0.0 0 0 ? SN Jan17 0:00 [ksmd] root 32 0.0 0.0 0 0 ? S Jan17 0:00 [aio/0] root 33 0.0 0.0 0 0 ? S Jan17 0:00 [aio/1] root 34 0.0 0.0 0 0 ? S Jan17 0:00 [crypto/0] root 35 0.0 0.0 0 0 ? S Jan17 0:00 [crypto/1] root 38 0.0 0.0 0 0 ? S Jan17 0:00 [khvcd] root 123 0.0 0.0 0 0 ? S Jan17 0:14 [kjournald] root 170 0.0 0.0 10408 4 ? S<s Jan17 0:00 udevd --daemon root 222 0.0 0.0 10404 4 ? S< Jan17 0:00 udevd --daemon root 223 0.0 0.0 10404 4 ? S< Jan17 0:00 udevd --daemon root 355 0.0 0.0 0 0 ? S Jan17 0:49 [rpciod/0] root 356 0.0 0.0 0 0 ? S Jan17 0:00 [rpciod/1] root 373 0.0 0.0 0 0 ? S< Jan17 0:00 [kslowd000] root 374 0.0 0.0 0 0 ? S< Jan17 0:00 [kslowd001] root 375 0.0 0.0 0 0 ? S Jan17 0:28 [nfsiod] root 395 0.0 0.0 0 0 ? S Jan17 0:03 [kjournald] root 495 0.0 0.0 6748 596 ? Ss Jan17 0:00 dhclient -v -pf root 788 0.0 0.0 43220 4 ? S Jan17 0:00 supervising sys root 789 0.0 0.1 51592 2912 ? Ss Jan17 0:39 /usr/sbin/syslo root 890 0.0 0.0 10208 104 ? Ss Jan17 0:00 /usr/sbin/inetd root 921 0.0 0.0 43112 344 ? Ss Jan17 0:05 /usr/sbin/sshd root 1014 0.0 0.0 0 0 ? S Jan17 0:00 [nfsv4.0-svc] root 1037 0.0 0.0 5928 8 hvc0 Ss+ Jan17 0:00 /sbin/getty 384 root 1780 0.0 0.1 74000 2296 ? SN Mar09 0:00 /USR/SBIN/CRON root 15461 0.0 0.1 59236 2076 ? Ss Jan19 0:12 /usr/sbin/cron root 21168 0.0 0.0 0 0 ? S Mar14 0:01 [flush-202:1] root 25915 0.0 0.2 89100 3932 ? SNs 02:23 0:00 sshd: csit2310 root 27443 0.0 0.2 89100 3964 ? SNs Mar16 0:00 sshd: skinney1 root 28768 0.0 0.0 0 0 ? S 08:35 0:00 [flush-0:17] root 29506 0.0 0.2 89100 3960 ? SNs 10:02 0:00 sshd: wedge [pr root 30082 0.0 0.2 89100 3988 ? SNs 10:48 0:00 sshd: smalik2 [ root 30157 0.0 0.1 58860 2076 ? Ss Mar14 0:02 /usr/sbin/rpc.i root 30213 0.0 0.1 167308 2236 ? Ssl Mar14 0:16 /usr/sbin/nscd root 30246 0.0 0.2 89100 4000 ? SNs 11:08 0:00 sshd: smalik2 [ root 30373 0.0 0.0 0 0 ? S 11:28 0:00 [flush-202:2] root 30418 0.0 0.2 89100 3984 ? SNs 11:35 0:00 sshd: jdavis34 root 30435 0.0 0.2 89100 4000 ? SNs 11:36 0:00 sshd: skinney1 root 30530 0.0 0.2 89100 3992 ? SNs 11:46 0:00 sshd: rmatsch [ root 31447 0.0 0.1 74000 2296 ? SN Mar09 0:00 /USR/SBIN/CRON root 31763 0.0 0.1 74004 1956 ? SN Mar14 0:00 /USR/SBIN/CRON root 32271 0.0 0.1 74000 2296 ? SN Mar09 0:00 /USR/SBIN/CRON root 32506 0.0 0.1 74000 2300 ? SN Mar13 0:00 /USR/SBIN/CRON lab46:~$
cron/crontab
cron tab is a task scheduler.It is a time based which runs periodically at certain times or dates, used to automate system processes.
lab46:~$ crontab -e # Edit this file to introduce tasks to be run by cron. # # Each task to run has to be defined through a single line # indicating with different fields when the task will be run # and what command to run for the task # # To define the time you can provide concrete values for # minute (m), hour (h), day of month (dom), month (mon), # and day of week (dow) or use '*' in these fields (for 'any').# # Notice that tasks will be started based on the cron's system # daemon's notion of time and timezones. # # Output of the crontab jobs (including errors) is sent through # email to the user the crontab file belongs to (unless redirected). # # For example, you can run a backup of all your user accounts # at 5 a.m every week with: # 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/ # # For more information see the manual pages of crontab(5) and cron(8) # # m h dom mon dow command
characters that are very powerful and help a great deal when in UNIX. the special characters enable a user to control the output of commands without having to specify the exact name of a file.
* zero or more of “any” character
? used to represent one of “any” character
\ will ignore such things as space if the variable name isn't one string.
” ” (or ' ') quote the enclosed characters
[ ] character class - match any of the enclosed characters.
[^ ] inverted character class - do not match any of the enclosed characters.
Pattern matching a way to search in unix which enables the user to look for files.
Using ls(1), list files that match the following patterns: a. Only files that begin with a lowercase vowel. b. All files that end with a .s c. All files that do not start with a vowel, yet end with a .s d. Only 3 character filenames that don't end with a consonant. e. Explain your strategy and reasoning for constructing an effective pattern for each part of this question
a. Using ls in the given directory, show me how you'd list only files
that begin with a lowercase vowel:
ls a* e* i* o* u*
b. Using ls in the given directory, show me how you'd list only files
that end with a .s:
ls *.s
c. Using ls in the given directory, show me how you'd list only files
that do not start with a vowel, yet end with a .s:
ls [b-d,f-h,j-n,p-t,v-z]**.s
d. Using ls in the given directory, show me how you'd list only the
files consisting of just 3 character filenames that don't end with a consonant:
lab46:/var/public/unix/patterns$ ls a* e* i* o* u* a.b.c.d.e.f.s abd i3 a39487y abe i4 a6.c abf i5.s a7.d ac.s i6.s a8.e aca i7.s a9.f ad.s ive_got_a_beautiful_feeling aaa alab5.s o_what_a_beautiful_day aab alab6.s o_what_a_beautiful_morning.s aac e11 u_2 aad e8933 uey aae e9038 uey2 aaf e904385 ueya ab.s ee.s ueyai aba everythings_going_my_way.s ueyed abb i1 uint abc i2 lab46:/var/public/unix/patterns$
tab completion
tab completion is a command line feature that allows you to type some of a command and have the command line finish it when you hit the tab key. kinda like a auto complete
Demonstration of the chosen keyword.
lab46:/var/public/unix/patterns$ l (tab) last less lispmtopgm lrrdNode lastb lessecho listres ls lastlog lessfile ln lsattr latin2ascii.py lesskey lnstat lscpu lcf lesspipe loadkeys lsinitramfs ld let loadunimap lsmod ld.bfd lex local lsof ld.gold lexgrog locale lspci ldapadd lft localedef lspgpot ldapcompare lft.db lockfile lsusb ldapdelete lftp lockfile-check luit ldapexop lftpget lockfile-create lwp-download ldapmodify libnetcfg lockfile-remove lwp-dump ldapmodrdn libpng-config lockfile-touch lwp-mirror ldappasswd libpng12-config loggen lwp-request ldapsearch line logger lwp-rget ldapurl link login lxterm ldapwhoami links logname lynx ldd links2 logout lynx.cur ldrdf linux32 look lzmainfo leaftoppm linux64 lorder
regular expressions
Regular Expression Symbol . Match any character * Match 0 or more of the preceding
$ End of line or string [ ] Character class - match any of the enclosed characters [^ ] Negated character class - do not match any of the enclosed characters \< Beginning of word \> End of word
grep '^[b-d][aeiou]' /etc/passwd
be able to write a simple shell scipt that contains file manipulation, and irc bot configuration.
the objective entails making a script to do multiple task incoporatiing things which have already learned allong with new task.
have students given many task and allow students to write all of these task in a script to be performed in a single script.
tell students to creat a script to do thing they know how to do via command line and also do task they dont know.
Reflect upon your results of the measurement to ascertain my achievement i did alright but there is always room for inprovmemt.
What happends when you leave out a semi colin on a struct.
struct weki pages
Based on what i read i think the result of your experiment will be a compile erroor. i believe this because funtions do not need them after curly brace but a struct would have to
i will create a struct and compile it to see if it compiles with out errors.
like i thought the semi colin is very important. i recieved a error when compiling
Based on the data collected:
my hypothesis correct, and applicable for the data collected.
based on the experiment performed and data collected leaving a semi colin out of a struct will cause an error when compiling. Error exspected expression.
when defining a funtion can you put a return type on a void funtion()
class notes void main() and int main()
based on class notes i the void main cannot have a return valuenbecause void main mean nothing is being returned.
i will create a void sum funtion and then type retutn(0); at the end pf the funtion. i will then compile and see what happends if any/
lab46:~/src/cprog/project2$ gcc -o prog2f prog2f.c prog2f.c: In function 'sum': prog2f.c:56: warning: 'return' with a value, in function returning void lab46:~/src/cprog/project2$
Based on the data collected my hypothesis was not correct but it was applicable. there was no short commings ut just a little more going on then exspected
===Conclusions===
based on the experiment performed and data collected having a return type to a void funtion will give a warning but will still compile.
brobbins exsperiment 1
Evaluate their resources and commentary. Answer the following questions:
Based on what I have learned about the C programming language thus far, I believe that the use of the exit command within a function will only cause the function to exit and not the entire program due to the fact that the exit argument would only be in scope with the current function and not the rest of the program.
This is the original code
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int iseven(int value)
{
int tmp;
tmp=value % 2;
return(tmp);
}
void add(int *list, int total, int value)
{
int i, s=0;
for(i=0; i < total; i++)
{
if(*(list+i)==-1)
{
*(list+i)=value;
s=i;
break;
}
}
}
int *init(int total, int *status)
{
int i, *tmp;
*status=0;
if(total > 0)
{
tmp=(int*)malloc(sizeof(int)*total);
for(i=0; i < total; i++)
{
*(tmp+i)=-1;
}
*status=1;
}
return(tmp);
}
int main(int argc, char **argv)
{
int *list, i, x=0;
list=init(atoi(*(argv+1)),&x);
if(x==0)
{
fprintf(stderr, "Error on initialization!");
exit(1);
}
for(i=0; i < atoi(*(argv+1)); i++)
{
add(list, atoi(*(argv+1)), (rand()%atoi(*(argv+2))));
}
for(i=0; i < atoi(*(argv+1)); i++)
{
if(iseven(*(list+i))==0)
{
fprintf(stdout, "%d is even\n", *(list+i));
}
else
fprintf(stdout, "%d is odd\n", *(list+i));
}
return(0);
}
This is the output received from the unmodified code.
lab46:~/src/cprog$ ./iseven 5 30 13 is odd 16 is even 27 is odd 25 is odd 23 is odd lab46:~/src/cprog$
The following is the code that has been modified to reflect the question above. Note the change in the “add” function, the “break” statement has been changed to an “exit” statement with a return code of zero. Also note the inclusion if the new printf statements within each function. These are included so I am able to tell how far the program progresses.
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int iseven(int value)
{
printf("Diag 1\n");
int tmp;
tmp=value % 2;
return(tmp);
}
void add(int *list, int total, int value)
{
printf("Diag 2\n");
int i, s=0;
for(i=0; i < total; i++)
{
if(*(list+i)==-1)
{
*(list+i)=value;
s=i;
exit(0);
}
}
}
int *init(int total, int *status)
{
printf("Diag 3\n");
int i, *tmp;
*status=0;
if(total > 0)
{
tmp=(int*)malloc(sizeof(int)*total);
for(i=0; i < total; i++)
{
*(tmp+i)=-1;
}
*status=1;
}
return(tmp);
}
int main(int argc, char **argv)
{
printf("Diag 4A\n");
int *list, i, x=0;
printf("Diag 4B\n");
list=init(atoi(*(argv+1)),&x);
printf("Diag 4C\n");
if(x==0)
{
fprintf(stderr, "Error on initialization!");
exit(1);
}
printf("Diag 4D\n");
for(i=0; i < atoi(*(argv+1)); i++)
{
printf("Diag 4Da\n");
add(list, atoi(*(argv+1)), (rand()%atoi(*(argv+2))));
printf("Diag 4Db\n");
}
for(i=0; i < atoi(*(argv+1)); i++)
{
if(iseven(*(list+i))==0)
{
fprintf(stdout, "%d is even\n", *(list+i));
}
else
fprintf(stdout, "%d is odd\n", *(list+i));
}
return(0);
}
The following is the resulting output after the modifications.
lab46:~/src/cprog$ ./iseven 5 30 Diag 4A Diag 4B Diag 3 Diag 4C Diag 4D Diag 4Da Diag 2 lab46:~/src/cprog$
In my UNIX class i learned how to better search through files and use the head(1) and sed(1) utility to take text out of the file i did not want. sed 's/pattern/replacement/g' = pattern searching for and then replace pattern searching for with this replacement and g means globally.head -25 file.txt = -n for number of lines you want to print of the file you choose which could then be piped to sed a stream editor to remove unwanted text. a basic line may look like this
head -25 file.txt | sed -e 's/[a-z]*5/:/g' print first 25 lines of file.txt and then search for text that start with a to z and end in 5 and once found replace that with colon globally in the file.
C++ class
A program can be split up into multiple files making it easier to edit and understand, especially in the case of large programs but also allows the individual parts to be compiled independently.
*when compiling a large program with multiple header file remember to add this line in the header file so you do not include the same header file twice in your program.
#ifndef _HEADERFILENAME_H #define _HEADERFILENAME_H
#endif
g++ -o prog file1.o file2.o file3.o compile c++ code into one executable named prog with the object files: file1 file2 file3. then you can now run ./prog on the command line because it is now an executable file.
To produce only .o files from source files without doing any linking invoke -c option
some html i did in unix class that diplayes an image of myself and some general info
<html> <title> RM Lab46 Homepage</title> <body> <center>Unix Homepage by Robert Matsch</center> <img src="player.jpg" height="42" width="42" /> <strong>Who am I :</strong> <p>My name is Robert matsch, I am currently a student at corning community college. Upon completion of my Computer Information Science degreein in may 2012 i am attending RIT for the fall of 2012. I am majoring in software engineering and planning to live in california once i graduate to work with my uncle and be part owner in a private consulting company.I enjoy listening to music, being active, riding my motorcycle and best of all spending time with friends and family. </p> <hr> <br> Top 6 movies: <ol> <li>Step Brothers</li> <li>Hangover 1 and 2 </li> <li>Finding Nemo</li> <li>Bad Boys II</li> <li>Talladega Nights</li> <li>k-pax</li> </ol> <p> </p> <br> who is I ? </body> </html>
<html> <title> RM Lab46 Homepage</title> <body> <center>Unix Homepage by Robert Matsch</center> <img src=“player.jpg” height=“42” width=“42” />
<strong>Who am I :</strong> <p>My name is Robert matsch, I am currently a student at corning community college. Upon completion of my Computer Information Science degreein in may 2012 i am attending RIT for the fall of 2012. I am majoring in software engineering and planning to live in california once i graduate to work with my uncle and be part owner in a private consulting company.I enjoy listening to music, being active, riding my motorcycle and best of all spending time with friends and family. </p> <hr> <br> Top 6 movies: <ol> <li>Step Brothers</li> <li>Hangover 1 and 2 </li> <li>Finding Nemo</li> <li>Bad Boys II</li> <li>Talladega Nights</li> <li>k-pax</li> </ol> <p>
</p> <br> who is I ? </body> </html>
This is a sample format for a dated entry. Please substitute the actual date for “Month Day, Year”, and duplicate the level 4 heading to make additional entries.
As an aid, feel free to use the following questions to help you generate content for your entries:
Remember that 4 is just the minimum number of entries. Feel free to have more.
• logic and operators (and, or, not, xor) • Scope (Block, Local, Global, File) • Type Casting • Structures (Declaration, Accessing Elements, Pointers to) • Type Casting Operators, Const-Volatility Specifiers (const, volatile) [C++] • Overloading (Functions, Operators) [C++] • Exception Handing (throw, try, catch) [C++] • Templates, STL (Standard Template Library) [C++]
logic operators are a logical operation on one or more logic inputs that produces a single logic output
a b | and or xor nor xnor nand notb nota F T | F T T F F T F T T T | T T F F T F F F F F | T F F T T T T T T F | F T T F F T T F
Converting one type of data into another type of data.
short a=2000; int b; b = (int) a; b = int (a); or short a=2000; int b; b=a;
Templates in C++ template are classes to provide common programming data structures and functions. STL- standard template library is a library of templates
#include<iostream>
using namespace std;
template <class T>
void myfunc (T val1, T val2, T val3)
{
T result;
result = val1 + val2 + val3;
cout << "First value is: " << val1 << endl;
cout << "Second value is: " << val2 << endl;
cout << "Third value is: " << val3 << endl;
cout << "The sum of all three are: " << result << endl;
cout << "The average of all three are: " << (T)(result/3) << endl;
}
int main()
{
// some c code here
return 0;
}
You can redefine a function of most built-in operators in C++ by overloading globally or on a class. key point * Overloaded operators are implemented as functions and can be “member functions or global functions”.
You can also overload a function name by declaring more than one function with the that name in the same scope. when the program is being run and the function is call the program matches parameters up to select the right function.
Operator overloading
#include <iostream> using namespace std; class complx { double real, imag; public: complx( double real = 0., double imag = 0.); // constructor complx operator+(const complx&) const; // operator+() }; // define constructor complx::complx( double r, double i ) { real = r; imag = i; } // define overloaded + (plus) operator complx complx::operator+ (const complx& c) const { complx result; result.real = (this->real + c.real); result.imag = (this->imag + c.imag); return result; } int main() { complx x(4,4); complx y(6,6); complx z = x + y; // calls complx::operator+()
and now function overloading
#include <iostream>
using namespace std;
void print(int i) {
cout << " Here is int " << i << endl;
}
void print(double f) {
cout << " Here is float " << f << endl;
}
void print(char* c) {
cout << " Here is char* " << c << endl;
}
int main() {
print(10);
print(10.10);
print("ten");
and now the output from this function over loading
lab46:~$ ./funoverl Here is int 10 Here is float 10.1 Here is char* ten
key words that can “catch exceptions” by placing a portion of code under exception inspection and enclosing that portion of code in a “try block”. it works When an exception circumstance comes about within that block, the exception is then thrown which transfers the control to the exception handler. If no exception is thrown the code continues normally.
#include <iostream> using namespace std; int main () { try { throw 20; } catch (int e) { cout << "An exception occurred. Exception Nr. " << e << endl; } return 0; }
block: C++ names can only be used in parts of a program called the “scope” of the name. unless otherwise acres from a member of that class scope. this is very important in C++ because scope determines when variables local to the scope are initialized.
Local scope:A name declared within a block is accessible only within that block and blocks enclosed by it and only after the point of declaration.
File scope: Any name declared outside all blocks or classes has file scope also known as namespace scope.
global scope: is names with file scope that are not declare objects are global names.
local scope
{
int i;
}
Notice the declaration of i is in a block enclosed by curly braces so i has local scope and is never accessible because there is no code accesses before the closing curly brace.
class area()
{
int x;
int y;
};
x and y can be used to access the class area through “.”or “→”
constant : makes that the type is constant but also the object shall not be modified. In doing so it may you may recieve undesired/undefined results such as compile time error compile-time error.
volatile: makes the type volatile and the object then be modified so that the compiler doesn't yell at you.
const int five = 5;
const double pi = 3.141593;
const objects may not be changed below is an example: <Code>
#include <stdio.h> #include <stdlib.h> int main() {
int result=0;
const int five = 5;
const double pi = 3.141593;
pi = 3.2;
five = 6;
result=five+pi;
return(0); } </code> compile msg below
lab46:~$ gcc -o const const.c const.c: In function 'main': const.c:9: error: assignment of read-only variable 'pi' const.c:10: error: assignment of read-only variable 'five'
Declaring : a structure it is in the form of a block of data which can contain different data types depending on means of a structure declaration.
Accessing elements: structure accessing is done by specify both the structure name (name of the variable) and the member name when accessing information stored in a structure.
Point:you can point to structs by deference them below is example
struct tag *st_per;
and we point it to our example structure with:
st_per = &my_struct;
struct person{ char *name;//or --char name[20]; unsigned char age; short int weight; float gpa; }; //struct differ from union bec struct allocate memory for each and dont share $ typedef struct person P; P p1,p2,p3,p4,p5; struct person p1; struct person p2; struct person p3,p4,p5; Accessing Members of a Structure p1.age = 29; point to : struct person *st_per; st_per = &my_struct; (*st_per).age = 63;
The course objective is to be able to successfully develop C code of a desired program. The program should work and any problems that come about can be figure out and finally manage the code with C++ and abstract details away for security and neatness.
Develop a program that will allow a simpler way of doing something from creating a program of your choice. Have what you wish to be able to do and then program with the requirements chosen. produce a finished result
I have develop a program that i thought was going to be easy and turned out my requirement i want i did not achieve so i changed them a little. the program accepts string and compares string to string for user authentication.
Reflect upon your results of the measurement to ascertain your achievement of the particular course objective.
■The UNIX Shell
■ Environment variable
■ Source Code, Object Code, Binary Code, Library……x
■ Source Code, Object Code, Binary Code, Library
■ Filtering
■ networking, UNIX Networking Tools
■ Security
■ X Window System
filtering is a way to process text in a usable manner for the goal that is in mind.
some filtering utilities
cat(1) - concatenate files cut(1) - cut text grep(1) - globally search for regular expression and print head(1) - print first “n” lines of output sed(1) - stream editor sort(1) - sort output tail(1) - print last “n” lines of output tr(1) - translate characters uniq(1) - filter out duplicate lines from sorted file wc(1) - word count
lab46:~$ cat sample.db name:sid:major:year:favorite candy* Jim Smith:105743:Economics:Sophomore:Lollipops* Adelle Wilson:594893:Sociology:Junior:Ju-Ju Fish* Sarah Billings:938389:Accounting:Freshman:Tic-Tacs* Eric Vincent:1001119:Biology:Freshman:Lollipops* Linus Torvalds:4432001:Computer Science:Senior:Snickers* Alan Cox:40049300:Computer Science:Senior:Whoppers* Alan Turing:40030333:Computer Science:Senior:Rock Candy* Eric Vincent:1001119:Biology:Freshman:Lollipops* John Doe:0000000:Unknown:Freshman:unknown* Leet Haxzor:31337:Business:Sophomore:Gobstoppers* Matthew Green:439478:Philosophy:Junior:Necco Wafers* Megan Tanner:372233:Physics:Junior:Zero Bar* Junior Mint:2228484:Liberal Arts:Junior:Junior Mints* Alan Wilson:22908948:Economics:Freshman:Whoppers* Kris Warner:8383833:Biology:Senior:Mars Bar* Jill Ashley:9939392:Chemistry:Freshman:Warheads* Francois Laroux:93938383:Anthropology:Sophomore:Bubblegum* lab46:~$ cat sample.db | grep Biology Eric Vincent:1001119:Biology:Freshman:Lollipops* Eric Vincent:1001119:Biology:Freshman:Lollipops* Kris Warner:8383833:Biology:Senior:Mars Bar* lab46:~$ cat sample.db | grep Biology | grep Lollipops Eric Vincent:1001119:Biology:Freshman:Lollipops* Eric Vincent:1001119:Biology:Freshman:Lollipops* lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f1 hello there lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f2 this lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f3 is lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f1,6 | sed -e 's/:/ /g' hello there text. lab46:~$ sort sample.db sorts alphabetically Adelle Wilson:594893:Sociology:Junior:Ju-Ju Fish* Alan Cox:40049300:Computer Science:Senior:Whoppers* Alan Turing:40030333:Computer Science:Senior:Rock Candy* Alan Wilson:22908948:Economics:Freshman:Whoppers* Eric Vincent:1001119:Biology:Freshman:Lollipops* Eric Vincent:1001119:Biology:Freshman:Lollipops* Francois Laroux:93938383:Anthropology:Sophomore:Bubblegum* Jill Ashley:9939392:Chemistry:Freshman:Warheads* Jim Smith:105743:Economics:Sophomore:Lollipops* John Doe:0000000:Unknown:Freshman:unknown* Junior Mint:2228484:Liberal Arts:Junior:Junior Mints* Kris Warner:8383833:Biology:Senior:Mars Bar* Leet Haxzor:31337:Business:Sophomore:Gobstoppers* Linus Torvalds:4432001:Computer Science:Senior:Snickers* Matthew Green:439478:Philosophy:Junior:Necco Wafers* Megan Tanner:372233:Physics:Junior:Zero Bar* Sarah Billings:938389:Accounting:Freshman:Tic-Tacs* name:sid:major:year:favorite candy* lab46:~$ head -5 sample.db "print first 5 lines" tail does opposite prints last -n lines of file specified name:sid:major:year:favorite candy* Jim Smith:105743:Economics:Sophomore:Lollipops* Adelle Wilson:594893:Sociology:Junior:Ju-Ju Fish* Sarah Billings:938389:Accounting:Freshman:Tic-Tacs* Eric Vincent:1001119:Biology:Freshman:Lollipops*
Security is ability to allow and/or deny access to information that is vital to any multi-user system.
To be able to change permissions, allow access for new directories created along with new files is just some of the basic but must be taken into account. below is a command line which will display the umask
lab46:~$ umask 0022 lab46:~$ touch newfile lab46:~$ ls -l newfile -rw-r--r-- 1 rmatsch lab46 0 Apr 21 12:18 newfile lab46:~$
This means your default umask is set to this meaning that any files you make will have this minused the full permissions so a normal file full permission would be 666 but now when a new file is created thanks to umask the permissions on the file in octal are 644 which mean the owner can read and write to the file and everyone else can only read and same for group.
lab46:~$ mkdir newdirect lab46:~$ ls -ld newdirect drwxr-xr-x 2 rmatsch lab46 6 Apr 21 12:19 newdirect
full permission on a directory is 777 so 777 -22 = 755 which is show above with the owner having read write execute and group and world having only read and execute privileges.so umask is a very important thing to know if you are considering security of the system and users.
When you don't have access:
lab46:~$ cd /root -bash: cd: /root: Permission denied lab46:~$ chmod 077 newdirect "change newdirect's permissions to 077" lab46:~$ cd newdirect -bash: cd: newdirect: Permission denied
The Unix shell is a command-line interpreter that provides a user interface for Unix/linus operating systems. Users directly operate with the computer by entering commands execute, create, delete, and various other operation. There is no “ button clicking like windows computers”
At a command line interpreter such as bash or various other you can search through files, list files,create new files, copy files, delete files, make directories, and so on.Below is a demonstration of the various nothing i talked about just showing you that all task or “moving around the sytem is done through commands.
lab46:~$ ls 2 badname.tgz newdirect CCC.sh bin phenny CCCclasses.sh class_notes phenny.tar.bz2 Desktop classlog.c regex.html Documents count.c sample.db Downloads data spring2010-20091022.html Maildir fall2010-20100315.html spring2010-20101113.html Music fall2010-20101113.html spring2011-20101105.html Pictures fall2011-20110417.html spring2011-20101113.html Public file spring2012-20111103.html Templates index.html src Videos lab1 stdout archives labD.sh winter2011-20101113.html badname motd lab46:~$ cp count.c count.xxxxxxxxxxxxxx lab46:~$ rm count.c rm: remove regular file `count.c'? y lab46:~$ mkdir newdirect2 lab46:~$ touch newfile lab46:~$ ls 2 bin newfile CCC.sh class_notes phenny CCCclasses.sh classlog.c phenny.tar.bz2 Desktop count.xxxxxxxxxxxxxx regex.html Documents data sample.db Downloads fall2010-20100315.html spring2010-20091022.html Maildir fall2010-20101113.html spring2010-20101113.html Music fall2011-20110417.html spring2011-20101105.html Pictures file spring2011-20101113.html Public index.html spring2012-20111103.html Templates lab1 src Videos labD.sh stdout archives motd winter2011-20101113.html badname newdirect badname.tgz newdirect2 lab46:~$ grep hey regex.html <td NOSAVE><b><u><font size=+1>Objective:</font></u></b> To become familiar with the UNIX command line through exposure to some simple commands. The student will also be presented with traditional UNIX conventions they are expected to become familiar with and use throughout the semester.</td> How have they changed?</td> lab46:~$ cd .. lab46:/home$ ls bherrin2 dh018304 hshaikh jsmit176 mdecker3 rmatsch tp001498 bhuffner dherman3 hwarren1 jstrong4 mdittler rmoses triley2 bkenne11 dlalond1 ian jsulli34 mearley1 rnewman ts004985 bobpauljr dmay5 javery9 jtongue2 mgough rpetzke1 wedge bort dmckinn2 jbaez jtreacy mguthri2 rraplee wezlbot bowlett1 dmurph14 jbamper jtripp mhenry9 rrichar8 wfischba brian dpadget8 jbarne13 jv001406 mkellogg rsantia4 wknowle1 brobbin4 dparson3 jbesecke jvanott1 mkelsey1 rshaw8 wroos bstoll dpotter8 jblaha jwalrat2 mmatt rthatch2 ystebbin btaber2 dprutsm2 jblanch1 jwhitak3 mowens3 ryoung12 zlittle bwheat drobie2 jbrant jwilli30 mp018526 sblake3 zmccann bwilso23 ds000461 jbrizzee jwilso39 mpage9 sc000826 zward lab46:/home$ cd rmatsch lab46:~$ cd src lab46:~/src$ ls Makefile cprog hello1 hello1.c helloC helloC.c submit unix lab46:~/src$ cd unix lab46:~/src/unix$ ls arc.tar.gz cs4.txt cs9.txt lab0.txt lab5.txt laba.txt contact.info cs5.txt csA.txt lab1.txt lab6.txt link.sh cs1.txt cs6.txt csB.txt lab2.txt lab8.txt scripting cs2.txt cs7.txt csC.txt lab3.txt lab9.txt shell cs3.txt cs8.txt devel lab4.txt labC.txt unix_html_stuff lab46:~/src/unix$
environment variables are significant and can be thought of in a sense to create the operating environment in which a process runs. environment variables set at login are valid for the duration of the session. Environment variables have UPPER CASE as opposed to lower case which are shell variables.
USER (your login name) HOME (the path name of your home directory) HOST (the name of the computer you are using) ARCH (the architecture of the computers processor) DISPLAY (the name of the computer screen to display X windows) PRINTER (the default printer to send print jobs) PATH (the directories the shell should search to find a command)
lab46:~$ echo $HOME /home/rmatsch lab46:~$ echo $PATH /home/rmatsch/bin:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games lab46:~$ echo $OSTYPE linux-gnu lab46:~$ echo $USER rmatsch lab46:~$ echo $home lab46:~$
a software system which provides a basis for GUI's and has good input device capability for computers. basically it is used to build graphical user interfaces for unix like operating systems originally designed for network connection.
tools used to gain networking information such as the host you are connected to and various other network data that may be useful.
some of the two most important networking tools i think are netstat, ping below are example of them to find information on dns server to see if packets or being sent and network information.
lab46:~$ ping localhost PING localhost.localdomain (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=1 ttl=64 time=0.045 ms 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=2 ttl=64 time=0.037 ms 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=3 ttl=64 time=0.038 ms 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=4 ttl=64 time=0.036 ms ^C --- localhost.localdomain ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 2997ms rtt min/avg/max/mdev = 0.036/0.039/0.045/0.003 ms netstat Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 lab46.offbyone.la:60002 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.lan:ssh mobile-198-228-20:58895 ESTABLISHED tcp 0 0 lab46.offbyone.la:47089 irc.offbyone.lan:ircd ESTABLISHED lab46:~$ netstat -ta Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:ssh *:* LISTEN tcp 0 0 *:35801 *:* LISTEN tcp 0 0 *:nfs *:* LISTEN tcp 0 0 *:3939 *:* LISTEN tcp 0 0 *:3333 *:* LISTEN tcp 0 0 lab46.offbyone.lan:5000 *:* LISTEN tcp 0 0 lab46.offbyone.lan:5007 *:* LISTEN tcp 0 0 *:59343 *:* LISTEN tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:csync2 *:* LISTEN tcp 0 0 lab46.offbyone.lan:4242 *:* LISTEN tcp 0 0 lab46.offbyone.la:60002 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.lan:ssh mobile-198-228-20:58895 ESTABLISHED tcp 0 0 lab46.offbyone.la:47089 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:47998 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:42140 auth1.offbyone.lan:ldap ESTABLISHED tcp 0 0 lab46.offbyone.la:45645 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:58347 vm31.student.lab:ssh ESTABLISHED tcp 0 0 lab46.offbyone.la:44392 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:51839 auth1.offbyone.lan:ldap ESTABLISHED tcp 0 0 lab46.offbyone.la:47426 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:33595 auth1.offbyone.lan:ldap ESTABLISHED tcp 0 0 lab46.offbyone.la:44549 irc.offbyone.lan:ircd ESTABLISHED netstat -s |less Ip: 44800188 total packets received 2 with invalid addresses 280120 forwarded 0 incoming packets discarded 44488743 incoming packets delivered 58096734 requests sent out 7068 outgoing packets dropped Icmp: 10051 ICMP messages received 28 input ICMP message failed. ICMP input histogram: destination unreachable: 9389 echo requests: 250 echo replies: 412 9622 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 659 redirect: 7068 echo request: 1645 echo replies: 250 IcmpMsg: InType0: 412 InType3: 9389 InType8: 250 OutType0: 250 OutType3: 659 OutType5: 7068 OutType8: 1645 Tcp: 80063 active connections openings 38145 passive connection openings 26780 failed connection attempts 4252 connection resets received 85 connections established 44040550 segments received 57184990 segments send out 96026 segments retransmited 0 bad segments received. 30648 resets sent Udp: 388512 packets received
Demonstration of the chosen keyword.
If you wish to aid your definition with a code sample, you can do so by using a wiki code block, an example follows:
/* * Sample code block */ #include <stdio.h> int main() { return(0); }
Alternatively (or additionally), if you want to demonstrate something on the command-line, you can do so as follows:
lab46:~$ cd src lab46:~/src$ gcc -o hello hello.c lab46:~/src$ ./hello Hello, World! lab46:~/src$
source code is code written by a programmer in a text editor, object code is the source code compiled and ready to be linked to the binary code which is the binary executable the processor reads. library can be thought of as a place where header files are located.
lab46:~$ vi hello.c lab46:~$ file hello.c hello.c: ASCII C program text lab46:~$ gcc -c hello.c lab46:~$ ls hello.c hello.o lab46:~$ file hello.o hello.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped lab46:~$ gcc -o helo hello.o lab46:~$ file helo helo: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped lab46:~$ file hello.o hello.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped lab46:~$ file hello.c hello.c: ASCII C program text
students should be able to set permissions on file directories ad be able to filter text using utilities
the objective entails using reg expression cut(1),tr(1), and many more tools to filter text and be familiar with unix security.
Tell students to find what the default file and directory access is set to and how to change that default permission using umask and have an understanding of what is happening. ask students to search through a document and put the information into a useable manner by filtering the document or database. students should also be asked to change the permissions using chmod utility and demonstrate a clear understanding in permissions and security
lab46:~$ umask 0022 lab46:~$ touch file lab46:~$ ls -l file -rwxr-xr-x 1 rmatsch lab46 7481 Apr 21 16:21 file lab46:~$ umask 000 lab46:~$ touch file2 lab46:~$ ls -l file2 -rw-rw-rw- 1 rmatsch lab46 0 Apr 21 16:21 file2 lab46:~$ umask 22 lab46:~$ mkdir newd lab46:~$ ls -ld drwx-----x 30 rmatsch lab46 4096 Apr 21 16:23 . lab46:~$ ls -ld newd drwxr-xr-x 2 rmatsch lab46 6 Apr 21 16:23 newd lab46:~$ umask 22 lab46:~$ chmd -bash: chmd: command not found lab46:~$ chmod 777 newd lab46:~$ ls -ld newd drwxrwxrwx 2 rmatsch lab46 6 Apr 21 16:23 newd lab46:~$
1 is execute read is 4 and write is 2
Reflect upon your results of the measurement to ascertain your achievement of the particular course objective.
what will happen if you remove #ndef #define #endif from header files and re compile
Class notes
I think the program will compile with out any problems.
take a c++ program with multiple header files and remove the #ndef statements and see what happens.
it compiled with out the statements.
Based on the data collected:
upon further investigation in small problems probably wont matter so much but with many header files and larger programs this could be a big plus to have.
can kids touch there parents private parts (C++ inheritance)
Mathew hass
no kids to parent relationships cannot touch there parents private parts because then it would not be a private class if the kid had a friend and then third parties could touch the parents private parts which is not good for security.
develop a program and set certain variables to private class and then try to access these variables via a kid of the parent.
Based on the data collected:
C++ is great for code management and for security purposes as data access..
josh Davis experiment “IF or not if” http://lab46.corning-cc.edu/opus/spring2012/jdavis34/start#experiment_if_or_not_if
Evaluate their resources and commentary. Answer the following questions:
What is the use of \n and to what effect does it have if in a simple program designed to print “hello world” if: 1. it exists.
2. it does not I feel their hypothesis is adequate in capturing the essence of what they're trying to discover. and there is no adjustments i would make.
Follow the steps given to recreate the original experiment. Answer the following questions:
there is not to many directions to establish how to do it if i did not have any knowledge of C I feel there room for improvement in the experiment instructions/description such as a small snip of code.
no it is a simple experiment so there structure would do.
#include <stdio.h>
int main()
{
printf("hello, world\n");
printf("hello,\n world");
return(0);
}
lab46:~$ gcc -o hello hello.c lab46:~$ ./hello hello, world hello, world
Answer the following:
Yes the data seems in-line with the author
There is no deviations.
Yes the stated hypothesis is adequate.
Answer the following:
\n will make a new line
Good job experiment was done well.