encryption

[Nino Tsankashvili]

I need to read text from a file character by character process it and put it into a file. It doesn't show any errors or warnings but still doesn't work. Any ideas?

 
#include <cstdlib>
#include <iostream>
#include <fstream>
#include <cctype>


using namespace std;



/****************************************************************************/
// get the value of the key, that the user wants to shift the text
int getKey()
{
    int key;

    cout << "Please enter the value of the key between 1 and 95" << endl;
    cin >> key;
    // check that the value of the key must be between 1 and 95
    while (key < 1 || key > 95)
    {
        cout << "Please enter the value of the key between 1 and 95" << endl;
        cin >> key;
    } // end while
    return key;
} // end function getKey

/****************************************************************************/
//get character from the plaintext.txt, ignore if the character is less than 32
//or greater than 126, return characters between 32 and  126
char getCharacter()
{
    char c;


    ifstream infile;
    infile.open("plaintext.txt");

    if ( !infile.is_open() )
    {
        cout << "ERROR: Unable to open file!" << endl;
        system("PAUSE");
        exit(1);
    }

    while (!infile.eof())
    {
        infile >> c;
        if ( c > 32 || c < 126)
            ;
        else
        infile.clear();
        infile.open("plaintext.txt");
        infile >> c;
    }


    return c;

}// end function getCharacter

/****************************************************************************/

char caesarsCipher (char &c, int &key)
{

    ofstream outfile;
    outfile.open("ciphertext.txt");

    if ( !outfile.is_open() )
    {
        cout << "ERROR; Unable to open file!" << endl;
        system("PAUSE");
        exit(1);
    }

    int encrypted;

    encrypted = c + key;

    if ( encrypted > 126 )

        encrypted = encrypted - 95;

    return encrypted;
}



int main()
{
    int key;
    char c;

    int getKey();
    char getCharacter();
    char caesarsCipher(char &, int &);

    getKey();
    getCharacter();
    caesarsCipher(c, key);




    cout << endl << "Done!" << endl;

    system("PAUSE");
    return EXIT_SUCCESS;

}

[coder777]

So what doesn't work?

A tip: Providing a relative path like "ciphertext.txt" might lead to a situation where the program searches in the wrong directory. Use an absolute path instead

[hanst99]

Use an absolute path instead

For debugging purposes maybe, but generally paths should be relative (except in situations where you can reasonable assume that a file will never be moved).

[codekiddy]

Hello Nino,
your code is:

while (!infile.eof())
    {
        infile >> c;
        if ( c > 32 || c < 126)
            ;
        else
        infile.clear();
        infile.open("plaintext.txt");
        infile >> c;
    }

this is bad approach IMO.

first line should be like this:

while (infile.good())
{
     ///....
}

that way you know that while loop will break for any kind of error, not just EOF

next this code:

        else
        infile.clear();
        infile.open("plaintext.txt");
        infile >> c;

not sure but it looks like a bad boy.

else statement should be enclosed with brackets I think?

        else
        {
              infile.clear();
              infile.open("plaintext.txt"); // file handle should be closed before reopening ?
              infile >> c;
         }

Not sure if that was your intention but you're overriding c variable.
so when while loop finishes your function returns what?

only last character, not all of them sorted!

according to your comment in the code the function is supposted to return a const char*

But in that case your c varaible should be defined outside the function or you should create a heap pointer to the char* and return that.

also in your main function,

int getKey();
are you declaring a function inside a main() ?

[Nino Tsankashvili]

thanks for replying you guys,
I'm not familiar with absolute path (you know, beginners :D ),
Codekiddy,
yes I'm decaring all of the functions inside the main, because all the functions are called by main only, I tried both of your suggestions but still no luck, when while loop finishes it should return single next character with ascii value between 32 and 126 only.