STDIN - Keyboard
STDOUT - Terminal
STDERR - Terminal
Printf(“”);
Fprintf(stdout,“___”); == What Printf does.
00000000 = 0
11111111 = 255
0-255 = 256 unique values
Printf format specifiers
%d = signed int
%v = unsigned int
%c = ASCII character(char)
%s = array of character(string)
%f = floating point
%lf = double
%lu = unsigned long int
%hu = unsigned half/short int
%hhu = unsigned half half int
%x = hexidecimal
%X = hexidecimal
0x00 = hexidecimal number
binary = 0,1
octal = 0-7
decimal = 0-9
hexidecimal = 0-9a-f
Hexidecimal | Octal | Unsigned Decimal | Binary | Signed Decimal |
---|---|---|---|---|
0 | 00 | 00 | 0000 | +0 |
1 | 01 | 01 | 0001 | +1 |
2 | 02 | 02 | 0010 | +2 |
3 | 03 | 03 | 0011 | +3 |
4 | 04 | 04 | 0100 | +4 |
5 | 05 | 05 | 0101 | +5 |
6 | 06 | 06 | 0110 | +6 |
7 | 07 | 07 | 0111 | +7 |
8 | 10 | 08 | 1000 | -8 |
9 | 11 | 09 | 1001 | -7 |
A | 12 | 10 | 1010 | -6 |
B | 13 | 11 | 1011 | -5 |
C | 14 | 12 | 1100 | -4 |
D | 15 | 13 | 1101 | -3 |
E | 16 | 14 | 1110 | -2 |
F | 17 | 15 | 1111 | -1 |
UD | B | SD |
---|---|---|
low : 0 | low:0000 | low:-8 |
high : 15 | high:1111 | high:+7 |
qty : 16 | qty:10000 | qty:16 |
MSB - Sign Bit
0 - +
1 = -
Two's Complement:
0001
to\\
1110 #invert
+ 1 #add one
1111
01111111
0x7F
10000000
0x80
Mental Math
2 digit numbers end in 5
15^2 = 225\
square second number 1|5^2
25
time 1st number by next number up
1*2=2
=225
int input; #variable
printf(“Enter Value:”);
Scanf(“%d”,&input); #address oaddress of
for(i=0; i<=strlen(input); i++)
for loop
for(i=13, i>2, i-=3)
i-=3 means i = i - 3
while - top-driven loop - 0 or more times
do while - bottom-driven loop - 1 or more times
while(condition) - no semi colon
{
do stuff
}
do
{
do stuff
}while(condition); always does one loop first
return type - int main(int argc, char **argv)
{
int x=4;
x = square(x);
return(0);
}
y = f(x) - X is a parameter
==Function Prototype== - int square(int);
look into recursion!
fgetc(stdin); = Gets Rid Of Enter As A Input! For Char Inputs!
printf(“%.4hhd - the four leaves to blank spaces before the output the . makes the spaces zero. if it was a -4 the two spaces would be after the output. hhd means half of a half of an integer - char.
a = 41
b = 4
printf(”%.*hhd\n“,b,a); The b allows 4 zeros before the 41 because b is set to 4, variable, can change!!
==Learning More With Arrays!!
Look at program array1
#include<stdio.h> int main() { int i, scores[8], sum = 0, total; float average; printf("How big is the array?"); scanf("%d",&total); scores=(int*)malloc(sizeof(int)*total); for(i=0;i<total;i++) { printf("Enter Test Score %d/%d: ",(i+1),total); scanf("%d",(scores+i)); } for(i=0;i<total;i++) { sum = sum + *(scores+i); // or scores[i] } average = sum/total; printf("average is: %3.2f\n",average);
gcc - C - .c
g++ - C++ - .C, .cc, .c++, .cpp
look in terminal for c++ starting program.
printf(“Hello, World!\n”); in C
std :: cout « “Hello, World!” « endl; in C++
scanf(”%d“ , &a); in C
cin » a; in C++
to use cin and cout MUST INCUDE #include<iostream>
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:
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:
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:
wiki.debian.org/Xen
ssh root@10.80.2.180
aptitude update aptitude upgrade aptitude search "VIM" , "Xen"- example aptitude install
hypervisor - kernel - user space
uname -a
install VIM and xen-linux-system
used Xen wiki to make Xen boot first!
vi /etc/network/interfaces
changed files according to Xen wiki
vi /etc/default/xendomains
do guest behaviour changes
restart server,
reboot
login run
xm list
xen-create-image --verbose --hostname=test --dhcp --vcpus=2 --pygrub --dist=wheezy --force
ssh root@10.80.2.197
== sign into my VM after ssh into lab46
Got the virtual machines up and running, had memory problem… Changed some of the ram sticks around and found the culprit and swapped it. The computer is up and running again. Re-created VM's!
Working with Virtual Machines, Mine being alex1. Installing packages such as Vim, bsdgames, etc. Learned how to run visual programs such as yahtzee by starting from the pod and running:
pod02:~$ ssh -X root@10.80.2.197
Created shortcuts in .bashrc such as
alias aps='aptitude search' alias api='aptitude install' alias apud='aptitude update' alias apug='aptitude upgrade'
Created Blackbeard User. Made The .vimrc and edited it.
Changed root@10.80.2.197 to root@vm04 for my sign on.
Creating Servers and Blogs Using Nginx and pybloxsom
Finally Got My Blog Up And Running!!! Figured Out The Flavours And Have The Nice 1024px! Check out http://vm04/cgi-bin/pyblosxom.cgi
Learned to create passwordless logins!!
Learned to take dumps in a new way!!
scp id_rsa.pub root@backup01:alex - copied to my root directory
cat alex » .ssh/authorized_keys - put my user into authorized keys
chmod 600 authorized_keys - changed permissions
cat authorized_keys - view the key
Continued taking dumps!!
dump -0uan -f - / | gzip -9 | ssh root@backup01 “dd of=blackbeard.dump.gz”
xm create - alex1 or wilson - Starting VM
blackbeard@router.projects.lan - arg
the type “su” to become root.
Then “screen -x” to join screen session.
Subnetcalc
on lab46
%s/252/192/ will change all the 252's into 192 in the vi.
4yy copy 4 lines in vi.
cw replaces text in vi.