Caesar Cipher in C++ - Overclock.net

tofunater · 10-15-09

I know you guys are probably getting sick of my programming questions, but you guys are a lot more helpful than my TA has ever been, so here it goes. I need to develop a reverse Caesar cipher (A=D. Z=C, etc) function as part of a larger program. I'm not sure what I've done wrong :

Code:

//Function 1 - undoes the Caesar Cipher
char revCaesar(char ch)
{
     if(isupper(ch))
            
           {
            if(ch <= D and ch >= Z)
                  {
                   int ch;
                   ch = ch - 3;
                   return ch;
                  }
            else
                
                switch(ch)
                            {
                            case 'A':
                            ch = "X";
                            break;
                            case 'B':
                            ch = "Y";
                            break;
                            case 'C':
                            ch = "Z";
                            break;
                            }
            return ch;
           }
     else
           {
            if(ch <= d or ch >= z)
                  {
                   int ch;
                   ch = ch - 3;
                   return ch;
                  }
            else
                  char s;
                  switch(ch)
                            {
                            case 'a':
                            s = "x";
                            break;
                            case 'b':
                            s = "y";
                            break;
                            case 'c':
                            s = "z";
                            break;
                            }
            return ch;
}
}

Any ideas?

Spotswood · 10-15-09

There are a lot of basic syntax errors in that function, but the most glaring mistake I see is that you should be calling isupper().

tofunater · 10-15-09

Quote:

Originally Posted by Spotswood

There are a lot of basic syntax errors in that function, but the most glaring mistake I see is that you should be calling isupper().

Seriously? My assignment notes must be wrong, dammit. Fixed it now. Would you notate the syntax errors for me, I really am lost as to what is wrong.

Spotswood · 10-15-09

Quote:

Originally Posted by tofunater

Seriously? My assignment notes must be wrong, dammit. Fixed it now. Would you notate the syntax errors for me, I really am lost as to what is wrong.

Code:

//Function 1 - undoes the Caesar Cipher
char revCaesar(char ch)
{
    if(isupper(ch))

    {
        if(ch <= D and ch >= Z)  // D and Z should be surrounded by single quotes
        {
            int ch;
            ch = ch - 3;
            return ch;
        }
        else

            switch(ch)
        {
            case 'A':
                ch = "X"; // use single quotes
                break;
            case 'B':
                ch = "Y";
                break;
            case 'C':
                ch = "Z";
                break;
        }
        return ch;
    }
    else
    {
        if(ch <= d or ch >= z)
        {
            int ch;
            ch = ch - 3;
            return ch;
        }
        else // missing {
            char s;
        switch(ch)
        {
        case 'a':
            s = "x"; // use single quotes
            break;
        case 'b':
            s = "y";
            break;
        case 'c':
            s = "z";
            break;
        }
        return ch;  // return s, no?
       // missing }
    }
}

tofunater · 10-15-09

thanks for that spotswood, and... that did it. Once again, my class notes failed me. The switch statements were modeled exactly off of what I was given

Pooping^fish · 4 Weeks Ago

Why is ch an int? Just use a char and the correct single quotes.
You need to define or quote D / Z.

Code:

if(ch <= d or ch >= z)
        {
            int ch;
            ch = ch - 3;
            return ch;
        }

Its going to use the ch within local scope. Essentially you just did (arb-value or 0) - = 3 it seems.

10-15-09	#2 (permalink)
Spotswood Case Modder Join Date: Jul 2008 Location: New Hampshire, USA Posts: 235 Rep: 46 Unique Rep: 39 Trader Rating: 0	There are a lot of basic syntax errors in that function, but the most glaring mistake I see is that you should be calling isupper(). __________________ Rich Custom Wooden Case Builder

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Caesar Cipher in C++

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