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--- user:sswimle1:portfolio:cprogproject1 [2012/02/24 16:25] – [Objectives] sswimle1
+++ user:sswimle1:portfolio:cprogproject1 [2012/02/28 23:28] (current) – [References] sswimle1
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+======Project: SECRET AGENT======
+A project for C/C++ Programing by Shane Swimley during the Spring 2012.
+This project was begun on 2/24/12 and is anticipated to take 1 day to complete. Project was completed on MONTH DAY, YEAR.
+=====Objectives=====
+State the purpose of this project. What is the point of this project? What do we hope to accomplish by undertaking it?
+Write a program that will encipher and decipher a given string of text.
+=====Prerequisites=====
+In order to successfully accomplish/perform this project, the listed resources/experiences need to be consulted/achieved:
+  * successful completion of project #0 and solid understanding of pertinent topics
+  * familiarity with memory allocation via **malloc(3)**
+  * familiarity with looking up C function parameters/information in the manual
+  * familiarity with if statements, especially in use for error detection
+  * familiarity with pointers and pointer arithmetic
+  * familiarity with loops
+  * file I/O
+=====Background=====
+State the idea or purpose of the project. What are you attempting to pursue?
+Making a program that will take a message, encipher the message and print the encipher message out to the screen and a location in memory.
+Then taking the enciphered message, and deciphering it back into the readable message, displaying that to the screen and in a location of memory.
+=====Scope=====
+This project will test your familiarity with more involved algorithms, storage, and control structures.
+Encoding is the process of converting a message into a coded form.
+Decoding is the reverse- retrieving that original message from an encoded form.
+In this project you will write a 2 programs: one that will take a plain text message and convert it into a coded form (largely indecipherable to the regular english expecting eye) using a given cipher key, and another that will reverse the process (or decipher), when given the appropriate key.
+The key is a numeric used to rotate the alphabet a set amount. Where A would normally equal 1, and Z 26, using a cipher key of 1 to shift 1 position to the right; A would now equal 2 (or B), B is now 3 (or C), and Z would be 1 (A).
+Your encoding program can operate as follows:
+  * obtains its cipher key from a text file called "key.txt"
+  * or, if you prefer, use command-line arguments to provide the key
+  * obtains the input message from a file called "message.txt"
+  * if "plain.txt" is blank, or does not exist, the program should prompt the user to enter the message via STDIN
+  * outputs the ciphertext message to STDOUT **AND** saves it to a file called "cipher.txt"
+  * implement error checking to avoid segfaults
+The decoding operation is essentially the reverse (shifting to the left). I'd suspect you could reuse much of the same logic.
+Your decoding program:
+  * obtains its cipher key from a text file called "key.txt"
+  * or, if you prefer, use command-line arguments to provide the key
+  * obtains the input cipher from a file called "cipher.txt"
+  * if "cipher.txt" is blank, or does not exist, the program should prompt the user to enter the message via STDIN
+  * outputs the plaintext message to STDOUT **AND** saves it to a file called "plain.txt"
+  * implement error checking to avoid segfaults
+If you want, you may implement both functionalities into one program so long as you provide a mechanism for the user to access both operations (but note this is not required for successful completion of this project).
+=====Code=====
+The encipher code:
+<code c>
+#include<stdio.h>
+#include<stdlib.h>
+int main()
+{
+        FILE *message, *key, *cipher;
+        char c, fname[] = "message.txt";
+        char code[] = "key.txt";
+        int keyvalue;
+        message = fopen(fname, "r");
+        key = fopen(code, "r");
+        cipher = fopen("cipher.txt", "w");
+        c = fgetc(message);
+        fscanf(key,"%d",&keyvalue);
+        printf("Message is: ");
+        while(c != EOF)
+        {
+                fprintf(stdout, "%c", c);
+                c = fgetc(message);
+        }
+        fclose(message);
+        message = fopen(fname, "r");
+        c = fgetc(message);
+        printf("Cipher is: ");
+        while(c != EOF)
+        {
+                if((c >= 65) && (c <= 'Z'))
+                        c = c + keyvalue;
+                else if((c >= 'a') && (c <= 'z'))
+                        c = c + keyvalue;
+                fprintf(stdout, "%c", c);
+                fprintf(cipher, "%c", c);
+                c = fgetc(message);
+        }
+        fclose(message);
+        fclose(key);
+        return(0);
+}
+</code>
+Don't forget your deciphering code as well.
+<code c>
+#include<stdio.h>
+#include<stdlib.h>
+int main()
+{
+        FILE *cipher, *key, *decipher;
+        char c, fname[] = "cipher.txt";
+        char code[] = "key.txt";
+        int keyvalue;
+        cipher = fopen(fname, "r");
+        key = fopen(code, "r");
+        decipher = fopen("decipher.txt", "w");
+        c = fgetc(cipher);
+        fscanf(key,"%d",&keyvalue);
+        printf("Cipher is: ");
+        while(c != EOF)
+        {
+                fprintf(stdout, "%c", c);
+                c = fgetc(cipher);
+        }
+        fclose(cipher);
+        cipher = fopen(fname, "r");
+        c = fgetc(cipher);
+        printf("Decipher is: ");
+        while(c != EOF)
+        {
+                if((c >= 65) && (c <= 'Z'))
+                        c = c - keyvalue;
+                else if((c >= 'a') && (c <= 'z'))
+                        c = c - keyvalue;
+                fprintf(stdout, "%c", c);
+                fprintf(decipher, "%c", c);
+                c = fgetc(cipher);
+        }
+        fclose(cipher)
+        fclose(key);
+        return(0);
+}
+</code>
+=====Execution=====
+An example run of the enciphering process:
+<cli>
+lab46:~/src/cprog$ ./project2
+Message is: deadbeef
+Cipher is: fgcfdggh
+lab46:~/src/cprog
+</cli>
+Now, we switch gears and decipher a different (previously enciphered) message:
+<cli>
+lab46:~/src/cprog$ gcc -o project2.1 project2.1.c
+lab46:~/src/cprog$ ./project2.1
+Cipher is: fgcfdggh
+Decipher is: deadbeef
+</cli>
+=====Reflection=====
+Comments/thoughts generated through performing the project, observations made, analysis rendered, conclusions wrought. What did you learn from doing this project?
+I do not think that the overall concept behind the code is hard part of a project like this for me, I think starting something like this from scratch after having about 5 weeks of C/C++ face time is the difficult part. Once I was introduced to concepts for completing the task I found that with little to no guidence I could write the decipher program on my own, starting the cipher program was the difficult part.
+Now that I have a working example I can take some more time to look at the code and improve my concept of creating something like this from scratch.
+=====References=====
+In performing this project, the following resources were referenced:
+Matt's example posted.
+Other students code.
+Generally, state where you got informative and useful information to help you accomplish this project when you originally worked on it (from Google, other wiki documents on the Lab46 wiki, etc.)

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