Thread: cipher

i am trying to write a simple caesar cipher.
reading in a text file and using an offset I can decode the file, but handling capitol letters are not working.. here is the code for decryption part

Code:

while (inputFile2)
{
      inputFile2.get(ch);
       if (ch == '@' || ch == '%')
        {
	outfile << ch;
           
        }
        else 
	if (islower(ch))
        {    
        ch = ch - offset;

        if ( ch < 'a' ) // 'A' for capitals.
        {
           ch = ch + 26;
        }
	outfile << ch;
       
        }
        else if (ch >= 'A' && ch <= 'Z')
        {
            ch = ch - offset;
	outfile << ch;
        
        }
        else if (ch == '#')
        {
            cout << endl << endl;
        }
        else if (ch == ' ' || ch == '\t' || ch == '\n')
        {
	outfile << ch;
        
        }
        else if (ch == '1' || ch == '2' || ch == '3' || ch == '4' || ch == '5' || ch == '6' || ch == '7' || ch == '8' || ch == '9')
        {
	outfile << ch;
          
        }
        }

as you can see below its not handling capitol letters good.
output:

Code:

:he Declaration of Independence of the :hirteen Colonies
In C5NG8E99 July 4 1776 

:he unanimous Declaration of the thirteen united 9tates of America

how would i implement uppercase?

they onlt thing i can seem to do is make it lower and decrypt it.

Code:

if ( isupper ( ch ) ) {

ch = tolower ( ch );
         
}