codebreaking program

Hi, im new to c++ and im trying to make a codebreaking program which works by reading a text file, working out which letter has the highest frequency and swapping it with e, etc.

Except i cant work out why it wont work lol, it runs untill the end of the codebreak function

Thanks for any help

Code:

#include <iostream> #include <fstream> //This section of the code includes the libaries needed to run the program using namespace std; // Im using standard namespaces through out the code void codebreak(char code[512]) //This creates a function called codebreak, which uses the input code[] { int x, lettotal, y, i, maxno, let[25]; //This creates all the integer variables used in my program, x, y and i are used for counting char decry[25], broke[512]; //This creates the array used to hold the correct order of the alphabet i = 0; maxno = 0; x = 0; lettotal = 0; y = 0; //This sets all the integers used to 0 for (int x = 0; x <=25;){ let[x] = 0; x = x + 1; } //This assigns 0 to every value in the array let[25] for (int x = 0; x <= 512; x++){ if (code[x] = 'a'){ let[0] = let[0] + 1 ; } if (code[x] = 'b'){ let[1] = let[1] + 1 ; } if (code[x] = 'c'){ let[2] = let[2] + 1 ; } if (code[x] = 'd'){ let[3] = let[3] + 1 ; } if (code[x] = 'e'){ let[4] = let[4] + 1 ; } if (code[x] = 'f'){ let[5] = let[5] + 1 ; } if (code[x] = 'g'){ let[6] = let[6] + 1 ; } if (code[x] = 'h'){ let[7] = let[7] + 1 ; } if (code[x] = 'i'){ let[8] = let[8] + 1 ; } if (code[x] = 'j'){ let[9] = let[9] + 1 ; } if (code[x] = 'k'){ let[10] = let[10] + 1 ; } if (code[x] = 'l'){ let[11] = let[11] + 1 ; } if (code[x] = 'm'){ let[12] = let[12] + 1 ; } if (code[x] = 'n'){ let[13] = let[13] + 1 ; } if (code[x] = 'o'){ let[14] = let[14] + 1 ; } if (code[x] = 'p'){ let[15] = let[15] + 1 ; } if (code[x] = 'q'){ let[16] = let[16] + 1 ; } if (code[x] = 'r'){ let[17] = let[17] + 1 ; } if (code[x] = 's'){ let[18] = let[18] + 1 ; } if (code[x] = 't'){ let[19] = let[19] + 1 ; } if (code[x] = 'u'){ let[20] = let[20] + 1 ; } if (code[x] = 'v'){ let[21] = let[21] + 1 ; } if (code[x] = 'w'){ let[22] = let[22] + 1 ; } if (code[x] = 'x'){ let[23] = let[23] + 1 ; } if (code[x] = 'y'){ let[24] = let[24] + 1 ; } if (code[x] = 'z'){ let[25] = let[25] + 1 ; } //This whole loops is used to count the frequency of letters in the given text and store the //values in the array called let[25] } while (y <= 25){ lettotal = lettotal + let[y]; y = y + 1; } //This works out the total numbers of letters used and stores it in the integer lettotal y = 0; while (y <= 25){ let[y] = let[y]/lettotal; y = y + 1; } while (y <= 25){ while (i <= 25){ if (let[i] > maxno){ maxno = i; } //This code checks to see if the item in the array is currently larger than the maximum //number(maxno) i = i+1; } if (y = 0){ decry[maxno] = 'e'; } if (y = 1){ decry[maxno] = 't'; } if (y = 2){ decry[maxno] = 'a'; } if (y = 3){ decry[maxno] = 'o'; } if (y = 4){ decry[maxno] = 'i'; } if (y = 5){ decry[maxno] = 'n'; } if (y = 6){ decry[maxno] = 's'; } if (y = 7){ decry[maxno] = 'h'; } if (y = 8){ decry[maxno] = 'r'; } if (y = 9){ decry[maxno] = 'd'; } if (y = 10){ decry[maxno] = 'l'; } if (y = 11){ decry[maxno] = 'c'; } if (y = 12){ decry[maxno] = 'u'; } if (y = 13){ decry[maxno] = 'm'; } if (y = 14){ decry[maxno] = 'w'; } if (y = 15){ decry[maxno] = 'f'; } if (y = 16){ decry[maxno] = 'g'; } if (y = 17){ decry[maxno] = 'y'; } if (y = 18){ decry[maxno] = 'p'; } if (y = 19){ decry[maxno] = 'b'; } if (y = 20){ decry[maxno] = 'v'; } if (y = 21){ decry[maxno] = 'k'; } if (y = 22){ decry[maxno] = 'j'; } if (y = 23){ decry[maxno] = 'x'; } if (y = 24){ decry[maxno] = 'q'; } if (y = 25){ decry[maxno] = 'z'; } let[maxno] = 0; i = 0; y = y + 1; } //This group of if statements is used to find out the correct sequence in the alphabet, by replacing the //letter with the highest frequency with e, etc. x = 0; for (int x = 0; x <= 512;){ if (code[x] != 'a'){ code[x] = decry[0]; } if (code[x] != 'b'){ code[x] = decry[1]; } if (code[x] != 'c'){ code[x] = decry[2]; } if (code[x] != 'd'){ code[x] = decry[3]; } if (code[x] != 'e'){ code[x] = decry[4]; } if (code[x] != 'f'){ code[x] = decry[5]; } if (code[x] != 'g'){ code[x] = decry[6]; } if (code[x] != 'h'){ code[x] = decry[7]; } if (code[x] != 'i'){ code[x] = decry[8]; } if (code[x] != 'j'){ code[x] = decry[9]; } if (code[x] != 'k'){ code[x] = decry[10]; } if (code[x] != 'l'){ code[x] = decry[11]; } if (code[x] != 'm'){ code[x] = decry[12]; } if (code[x] != 'n'){ code[x] = decry[13]; } if (code[x] != 'o'){ code[x] = decry[14]; } if (code[x] != 'p'){ code[x] = decry[15]; } if (code[x] != 'q'){ code[x] = decry[16]; } if (code[x] != 'r'){ code[x] = decry[17]; } if (code[x] != 's'){ code[x] = decry[18]; } if (code[x] != 't'){ code[x] = decry[19]; } if (code[x] != 'u'){ code[x] = decry[20]; } if (code[x] != 'v'){ code[x] = decry[21]; } if (code[x] != 'w'){ code[x] = decry[22]; } if (code[x] != 'x'){ code[x] = decry[23]; } if (code[x] != 'y'){ code[x] = decry[24]; } if (code[x] != 'z'){ code[x] = decry[25]; } x = x + 1; } //This loop is used to replace every letter in the array code[] with the correct replacement //according to frequency for (int x = 0; x <=512;){ broke[x] = code[x]; x = x + 1; } cout << "\nAfter code breaking:\n" << broke << endl; } int main() //This defines the main() function { char file[256]; char code[512]; int i; i = 0; //This defines the arrays and integers used in the main function ifstream inFile; //This open the stream inFile system("cls"); //This clears the output screen cout << " Code Breaker!" << endl; cout << "Please enter the name and extension of the file you want to decode:" << endl; cin.getline ( file, 512, '\n'); cout << "The name entered was : " << file << endl; //This code gets the user to enter the name of the file that they wish to decode inFile.open(file); //This opens the text file specified by the user if (!inFile) { cerr << "Unable to open file"; exit(1); } //The code checks to see if the file opened correctly, if not, the program will end while(inFile >> code[i] && i < 512){ i = i + 1; } //This puts the data that was in the users file, into the array code cout << "This file contains the code : \n \n" << code << "\n" << endl; cout << "Now performing code breaking..." << endl; codebreak (code); inFile.close(); return 0; }

Re: codebreaking program

A couple of notes:

Code:

for (int x = 0; x <= 512; x++){ if (code[x] = 'a'){ let[0] = let[0] + 1 ; } if (code[x] = 'b'){ ....

This can be written as

Code:

for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } }

Saves you MANY lines of code. Try to do similar things whereever else you have those constructs.

Code:

y = 0; while (y <= 25){ let[y] = let[y]/lettotal; y = y + 1; }

This sets the whole let array back to zeros. Dividing an integer by a greater integer gives zero.

Last: Learn how to use your debugger and debug the program ;-)

Re: codebreaking program

Welcome to the forum!

There are little people who properly use code tags in their first posting, very well!

There are some issues that needs some attention:

- does your alphabet contain only 25 letters? You´re using a 25-element array and then address the 26th element. In C++ arrays are indexed from 0 to N-1, so valid indexes for int code[512] are 0-511.
- you are using x as local variable and a loop variable, this may cause some confusion.
- name your variables properly. i,x,y and let are valid names, but no one will know what you are using them for.
- get rid of the huge switch-case statement. Just check if the current letter is >= 'a' and <= 'z'. If it is you can calculate the corresponding index by subtracting 'a' from the letter: iLetterIndex = code[x] - 'a'
- use uniform loops. There are 3 different notations which do all the same:
- for( int x = 0; x < y; x++ )
- for( int x = 0; x < y ) { x++ };
- int x = 0; while( x < y ) { x++ }
- you´re accumulating the total number of letters used and then divide the individual letter count by the sum. Because you´re using integers the result will always be 0.
- you´re not resetting y to 0 before entering a while() loop

Re: codebreaking program

Thanks for your help, ill make the changes now.

Btw my let[25] array is 25 because an array starts from 0

Re: codebreaking program

Quote:

Originally Posted by boburob

Thanks for your help, ill make the changes now.

Btw my let[25] array is 25 because an array starts from 0

You are mistaking.

Code:

char arr[2]; // Array of size two arr[0] = 'a'; // first element arr[1] = 'b'; // second element arr[2] = 'c'; // illegal access !! char let[25]; // array of size 25

Re: codebreaking program

Oh lol, sorry i was always told to do it like that

Re: codebreaking program

Ive changed my program and its running now but this section of code

Code:

for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } }

Is not working, the let array always ends up holding 0012F91C

Re: codebreaking program

0012F91C sounds like the memory address where let starts. To print out let, use a loop like

Code:

for (int i=0; i<26; ++i) cout << 'a'+i << ": " << let[i] << '\n';

1 Attachment(s)

Re: codebreaking program

Yes you were right, the let is working but the decry array is not, i have attatched a screenshot of what happens when its run, the first group of 26 is the let array and the second is the decry array

Re: codebreaking program

Quote:

Originally Posted by GNiewerth

- you´re not resetting y to 0 before entering a while() loop

Please try to work through what people already posted. Then post your new code with the new error.

Re: codebreaking program

Quote:

Originally Posted by boburob

Ive changed my program and its running now but this section of code

Code:

for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } }

Is not working, the let array always ends up holding 0012F91C

What did treuss and I tell you about array dimensions?

Re: codebreaking program

Sorry, I had already made all the changes you said before, heres the new code

Code:

#include <iostream> #include <fstream> //This section of the code includes the libaries needed to run the program using namespace std; // Im using standard namespaces through out the code void codebreak(char code[513]) //This creates a function called codebreak, which uses the input code[] { int x, lettotal, y, i, maxno, let[26]; //This creates all the integer variables used in my program, x, y and i are used for counting char decry[26], broke[513]; //This creates the array used to hold the correct order of the alphabet i = 0; maxno = 0; x = 0; lettotal = 0; y = 0; //This sets all the integers used to 0 for (int x = 0; x <=25;){ let[x] = 0; x = x + 1; } //This assigns 0 to every value in the array let[25] for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } } //This section checks to see what charator is held in each element of the array code so I can work out the total letal frequncies y = 0; i = 0; while (y <= 25){ while (i <= 25){ if (let[i] > maxno){ maxno = i; } //This code checks to see if the item in the array is currently larger than the maximum //number(maxno) i++; } if (y = 0){ decry[maxno] = 'e'; } if (y = 1){ decry[maxno] = 't'; } if (y = 2){ decry[maxno] = 'a'; } if (y = 3){ decry[maxno] = 'o'; } if (y = 4){ decry[maxno] = 'i'; } if (y = 5){ decry[maxno] = 'n'; } if (y = 6){ decry[maxno] = 's'; } if (y = 7){ decry[maxno] = 'h'; } if (y = 8){ decry[maxno] = 'r'; } if (y = 9){ decry[maxno] = 'd'; } if (y = 10){ decry[maxno] = 'l'; } if (y = 11){ decry[maxno] = 'c'; } if (y = 12){ decry[maxno] = 'u'; } if (y = 13){ decry[maxno] = 'm'; } if (y = 14){ decry[maxno] = 'w'; } if (y = 15){ decry[maxno] = 'f'; } if (y = 16){ decry[maxno] = 'g'; } if (y = 17){ decry[maxno] = 'y'; } if (y = 18){ decry[maxno] = 'p'; } if (y = 19){ decry[maxno] = 'b'; } if (y = 20){ decry[maxno] = 'v'; } if (y = 21){ decry[maxno] = 'k'; } if (y = 22){ decry[maxno] = 'j'; } if (y = 23){ decry[maxno] = 'x'; } if (y = 24){ decry[maxno] = 'q'; } if (y = 25){ decry[maxno] = 'z'; } let[maxno] = 0; i = 0; y++; maxno = 0; } //This group of if statements is used to find out the correct sequence in the alphabet, by replacing the //letter with the highest frequency with e, etc. x = 0; for (int x = 0; x <= 512; x++){ if (code[x] != 'a'){ code[x] = decry[0]; } if (code[x] != 'b'){ code[x] = decry[1]; } if (code[x] != 'c'){ code[x] = decry[2]; } if (code[x] != 'd'){ code[x] = decry[3]; } if (code[x] != 'e'){ code[x] = decry[4]; } if (code[x] != 'f'){ code[x] = decry[5]; } if (code[x] != 'g'){ code[x] = decry[6]; } if (code[x] != 'h'){ code[x] = decry[7]; } if (code[x] != 'i'){ code[x] = decry[8]; } if (code[x] != 'j'){ code[x] = decry[9]; } if (code[x] != 'k'){ code[x] = decry[10]; } if (code[x] != 'l'){ code[x] = decry[11]; } if (code[x] != 'm'){ code[x] = decry[12]; } if (code[x] != 'n'){ code[x] = decry[13]; } if (code[x] != 'o'){ code[x] = decry[14]; } if (code[x] != 'p'){ code[x] = decry[15]; } if (code[x] != 'q'){ code[x] = decry[16]; } if (code[x] != 'r'){ code[x] = decry[17]; } if (code[x] != 's'){ code[x] = decry[18]; } if (code[x] != 't'){ code[x] = decry[19]; } if (code[x] != 'u'){ code[x] = decry[20]; } if (code[x] != 'v'){ code[x] = decry[21]; } if (code[x] != 'w'){ code[x] = decry[22]; } if (code[x] != 'x'){ code[x] = decry[23]; } if (code[x] != 'y'){ code[x] = decry[24]; } if (code[x] != 'z'){ code[x] = decry[25]; } } //This loop is used to replace every letter in the array code[] with the correct replacement //according to frequency for (int x = 0; x <=512;){ broke[x] = code[x]; x++; } cout << "\nAfter code breaking:\n" << broke << endl; for (int i=0; i<26; ++i){ cout << "" << i << ": " << let[i] << '\n'; } for (int i=0; i<26; ++i){ cout << "" << i << ": " << decry[i] << '\n'; } } int main() //This defines the main() function { char file[256]; char code[513]; int i; i = 0; //This defines the arrays and integers used in the main function ifstream inFile; //This open the stream inFile system("cls"); //This clears the output screen cout << " Code Breaker!" << endl; cout << "Please enter the name and extension of the file you want to decode:" << endl; cin.getline ( file, 512, '\n'); cout << "The name entered was : " << file << endl; //This code gets the user to enter the name of the file that they wish to decode inFile.open(file); //This opens the text file specified by the user if (!inFile) { cerr << "Unable to open file"; exit(1); } //The code checks to see if the file opened correctly, if not, the program will end while(inFile >> code[i] && i < 512){ i = i + 1; } //This puts the data that was in the users file, into the array code cout << "This file contains the code : \n \n" << code << "\n" << endl; cout << "Now performing code breaking..." << endl; codebreak (code); inFile.close(); return 0; }

Re: codebreaking program

What´s this all about?

Code:

for (int x = 0; x <= 512; x++){ if (code[x] != 'a'){ code[x] = decry[0]; } if (code[x] != 'b'){ code[x] = decry[1]; } if (code[x] != 'c'){ code[x] = decry[2]; } if (code[x] != 'd'){ code[x] = decry[3]; } if (code[x] != 'e'){ code[x] = decry[4]; } if (code[x] != 'f'){ code[x] = decry[5]; } if (code[x] != 'g'){ code[x] = decry[6]; } if (code[x] != 'h'){ code[x] = decry[7]; } if (code[x] != 'i'){ code[x] = decry[8]; } if (code[x] != 'j'){ code[x] = decry[9]; } if (code[x] != 'k'){ code[x] = decry[10]; } if (code[x] != 'l'){ code[x] = decry[11]; } if (code[x] != 'm'){ code[x] = decry[12]; } if (code[x] != 'n'){ code[x] = decry[13]; } if (code[x] != 'o'){ code[x] = decry[14]; } if (code[x] != 'p'){ code[x] = decry[15]; } if (code[x] != 'q'){ code[x] = decry[16]; } if (code[x] != 'r'){ code[x] = decry[17]; } if (code[x] != 's'){ code[x] = decry[18]; } if (code[x] != 't'){ code[x] = decry[19]; } if (code[x] != 'u'){ code[x] = decry[20]; } if (code[x] != 'v'){ code[x] = decry[21]; } if (code[x] != 'w'){ code[x] = decry[22]; } if (code[x] != 'x'){ code[x] = decry[23]; } if (code[x] != 'y'){ code[x] = decry[24]; } if (code[x] != 'z'){ code[x] = decry[25]; }

Does the snippet do what you intend to? Furthermore, using a switch statement enhances readability.

Re: codebreaking program

After you filled the let array, your code stops to make sense. Please first describe for yourself what the decry array is supposed to contain, then write down a detailed step-by-step algorithm how you can create the array content.

And please make your code more readable by following the hints already posted:

Quote:

Originally Posted by GNiewerth

- get rid of the huge switch-case statement. Just check if the current letter is >= 'a' and <= 'z'. If it is you can calculate the corresponding index by subtracting 'a' from the letter: iLetterIndex = code[x] - 'a'
- use uniform loops. There are 3 different notations which do all the same:
- for( int x = 0; x < y; x++ )
- for( int x = 0; x < y ) { x++ };
- int x = 0; while( x < y ) { x++ }

Re: codebreaking program

Sorry im fairly new at c++ so alot of the stuff you said i didnt get:/

Code:

for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } }

This works out a letter total from a text file

Code:

while (y <= 25){ while (i <= 25){ if (let[i] > maxno){ maxno = i; } //This code checks to see if the item in the array is currently larger than the maximum //number(maxno) i++; } if (y = 0){ decry[maxno] = 'e'; } if (y = 1){ decry[maxno] = 't'; } if (y = 2){ decry[maxno] = 'a'; } if (y = 3){ decry[maxno] = 'o'; } if (y = 4){ decry[maxno] = 'i'; } if (y = 5){ decry[maxno] = 'n'; } if (y = 6){ decry[maxno] = 's'; } if (y = 7){ decry[maxno] = 'h'; } if (y = 8){ decry[maxno] = 'r'; } if (y = 9){ decry[maxno] = 'd'; } if (y = 10){ decry[maxno] = 'l'; } if (y = 11){ decry[maxno] = 'c'; } if (y = 12){ decry[maxno] = 'u'; } if (y = 13){ decry[maxno] = 'm'; } if (y = 14){ decry[maxno] = 'w'; } if (y = 15){ decry[maxno] = 'f'; } if (y = 16){ decry[maxno] = 'g'; } if (y = 17){ decry[maxno] = 'y'; } if (y = 18){ decry[maxno] = 'p'; } if (y = 19){ decry[maxno] = 'b'; } if (y = 20){ decry[maxno] = 'v'; } if (y = 21){ decry[maxno] = 'k'; } if (y = 22){ decry[maxno] = 'j'; } if (y = 23){ decry[maxno] = 'x'; } if (y = 24){ decry[maxno] = 'q'; } if (y = 25){ decry[maxno] = 'z'; } let[maxno] = 0; i = 0; y++; maxno = 0; }

This code works out which letter in the text had the highest frequency, then it assigns e, the highest appearing letter in the alphabet, to the letters place in a new array decry, and continues doing this through this list

Re: codebreaking program

Uh, note that y = 0 assigns 0 to y. You probably want to compare instead, with y == 0.

Re: codebreaking program

Quote:

Originally Posted by boburob

Sorry im fairly new at c++ so alot of the stuff you said i didnt get:/

Not a problem. As both loops (outer and inner) loop from 0 to 25, use a for loop. Makes things more readable.

Quote:

Originally Posted by boburob

This code works out which letter in the text had the highest frequency, then it assigns e, the highest appearing letter in the alphabet, to the letters place in a new array decry, and continues doing this through this list

In addition to what lazerlight pointed out, please describe (in detail) what your variable "maxno" represents.

To shorten your code, define a string

Code:

const char chartable[] = "etaoinshrdlcumwfgypbvkjxqz";

chartable[y] will then be 'e' for y=0, 't' for y=1, ... 'z' for y=25.

Re: codebreaking program

You still don´t apply the advice you were given...

Please replace loops like

Code:

int x = 0; while( x <= 25 ) { // do some stuff x++; }

with

Code:

for( int x = 0; x <= 25; x++ ) { // do some stuff }

What do you think does this line of code do:

Code:

if( y = 0 ) { // do something }

PS:
Laserlight already answered this question. It´s good practice to place constants on the left side of a comparison, so the compiler yields an error message when you accidentally miss one = character:

Code:

if( a = 1 ) ... // ok, compiler won´t complain if( 1 = a ) ... // compiler yields an error message because 1 is a constant

Re: codebreaking program

Ive made all the changes , hopefully its easier to understand now, both the arrays are working but its only outputting whatevers at the end of the decry array

Code:

#include <iostream> #include <fstream> //This section of the code includes the libaries needed to run the program using namespace std; // Im using standard namespaces through out the code void codebreak(char code[513]) //This creates a function called codebreak, which uses the input code[] { int x, lettotal, y, i, maxno, let[26], maxpos; //This creates all the integer variables used in my program, x, y and i are used for counting char decry[26], broke[513]; //This creates the array used to hold the correct order of the alphabet const char chartable[] = "etaoinshrdlcumwfgypbvkjxqz"; const char chartable2[] = "abcdefghijklmnopqrstuvwxyz"; i = 0; maxno = 0; x = 0; lettotal = 0; y = 0; maxpos = 0; //This sets all the integers used to 0 for (int x = 0; x <=25; x++){ let[x] = 0; } //This assigns 0 to every value in the array let[25] for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } } //This section checks to see what charator is held in each element of the array code so I can work out the total letal frequncies for (int y = 0; y <= 25; y++){ for (int i = 0; i <= 25; i++){ if (let[i] > maxno){ maxno = let[i]; maxpos = i; } //This code checks to see if the item in the array is currently larger than the maximum //number(maxpos) } decry[maxpos] = chartable[y]; let[maxpos] = 0; maxno = 0; maxpos = 0; } //This group of if statements is used to find out the correct sequence in the alphabet, by replacing the //letter with the highest frequency with e, etc. for (int x = 0; x <= 512; x++){ for (int i = 0; i <=25; i++){ if (code[x] = chartable2[i]){ broke[x] = decry[i]; } } } //This loop is used to replace every letter in the array code[] with the correct replacement //according to frequency cout << "\nAfter code breaking:\n" << broke << endl; for (int i=0; i<26; ++i){ cout << "" << i << ": " << decry[i] << '\n'; } } int main() //This defines the main() function { char file[256]; char code[513]; int i; i = 0; //This defines the arrays and integers used in the main function ifstream inFile; //This open the stream inFile system("cls"); //This clears the output screen cout << " Code Breaker!" << endl; cout << "Please enter the name and extension of the file you want to decode:" << endl; cin.getline ( file, 512, '\n'); cout << "The name entered was : " << file << endl; //This code gets the user to enter the name of the file that they wish to decode inFile.open(file); //This opens the text file specified by the user if (!inFile) { cerr << "Unable to open file"; exit(1); } //The code checks to see if the file opened correctly, if not, the program will end while(inFile >> code[i] && i < 512){ i = i + 1; } //This puts the data that was in the users file, into the array code cout << "This file contains the code : \n \n" << code << "\n" << endl; cout << "Now performing code breaking..." << endl; codebreak (code); inFile.close(); return 0; }

Thanks for all your help so far

Re: codebreaking program

Quote:

Originally Posted by boburob

Ive made all the changes , hopefully its easier to understand now, now the let array is not working although ive made no changes:S

Not yet ;) There are still two loops where you increment the loop variable inside the loop´s body.
Next check if you can eliminate some variables from your function, it looks like as if you don´t need them all.
You still don´t name your variables properly. It´s ok to name variables x, y and i when using them in loops, but you should give them meaningful names. The same applies to the char tables, why don´t you name them PlainCharTable and CipherCharTable (or similar)?

What´s the content of your let array?

Re: codebreaking program

Lol ok i think now all the changes are made, the let array is working, but its just outputting whatever was in the last position of the decry array

Code:

#include <iostream> #include <fstream> //This section of the code includes the libaries needed to run the program using namespace std; // Im using standard namespaces through out the code void codebreak(char code[513]) //This creates a function called codebreak, which uses the input code[] { int x = 0, i = 0, maxno = 0, let[26], maxpos = 0; //This creates all the integer variables used in my program, x and i are used for counting char decry[26], broke[513]; //This creates the array used to hold the correct order of the alphabet const char ciphertable[] = "etaoinshrdlcumwfgypbvkjxqz"; const char normaltable[] = "abcdefghijklmnopqrstuvwxyz"; //This sets all the integers used to 0 for (int x = 0; x <=25; x++){ let[x] = 0; } //This assigns 0 to every value in the array let[25] for (int x = 0; x <= 512; x++){ if (code[x] >= 'a' && code[x] <= 'z') { let[code[x]-'a']++; } } //This section checks to see what charator is held in each element of the array code so I can work out the total letal frequncies for (int x = 0; x <= 25; x++){ for (int i = 0; i <= 25; i++){ if (let[i] > maxno){ maxno = let[i]; maxpos = i; } //This code checks to see if the item in the array is currently larger than the maximum //number(maxpos) } decry[maxpos] = ciphertable[x]; let[maxpos] = 0; maxno = 0; maxpos = 0; } //This group of if statements is used to find out the correct sequence in the alphabet, by replacing the //letter with the highest frequency with e, etc. for (int x = 0; x <= 512; x++){ for (int i = 0; i <=25; i++){ if (code[x] = normaltable[i]){ broke[x] = decry[i]; } } } //This loop is used to replace every letter in the array code[] with the correct replacement //according to frequency cout << "\nAfter code breaking:\n" << broke << endl; for (int i=0; i<26; ++i){ cout << "" << i << ": " << decry[i] << '\n'; } } int main() //This defines the main() function { char file[256]; char code[513]; int i = 0; //This defines the arrays and integers used in the main function ifstream inFile; //This open the stream inFile system("cls"); //This clears the output screen cout << " Code Breaker!" << endl; cout << "Please enter the name and extension of the file you want to decode:" << endl; cin.getline ( file, 512, '\n'); cout << "The name entered was : " << file << endl; //This code gets the user to enter the name of the file that they wish to decode inFile.open(file); //This opens the text file specified by the user if (!inFile) { cerr << "Unable to open file"; exit(1); } //The code checks to see if the file opened correctly, if not, the program will end while(inFile >> code[i] && i < 512){ i = i + 1; } //This puts the data that was in the users file, into the array code cout << "This file contains the code : \n \n" << code << "\n" << endl; cout << "Now performing code breaking..." << endl; codebreak (code); inFile.close(); return 0; }

Re: codebreaking program

Quote:

Originally Posted by boburob

Lol ok i think now all the changes are made, the let array is working, but its just outputting whatever was in the last position of the decry array

Again: = and == are different things ;)

Some more comments: You should initialize maxno to -1, not to 0. Otherwise characters which do not appear in the code are not mapped at all (admitted: this won't affect the decrypted output). Likewise, set let[maxpos] to -1.

Another thing: Use

Code:

for (int i = 0; i < 26; ++i)

instead off

Code:

for (int i = 0; i <= 25; ++i)

It's does not make a difference, but the first syntax causes less confusion, as you will only have one number (26) in the code and never 25. Likewise with 512/513.

Re: codebreaking program

Thank you everyone for your help, it is now working:D