C++ errors

[uNr34l_w0m4N]

assignment: 4.4. Internet mailers and news-readers often contain a "rot13"
function that can be used to "encrypt" words by
rotating their characters 13 positions
(i.e., A becomes N, B becomes O, C becomes P, ... Z becomes M).
This is convenient, because the same function can be used
to both "encrypt" and "decrypt" a word:
rot13("ROMEO") == "EBZRB"
and
rot13("EBZRB") == "ROMEO"
Write a Rot13() function that, given a string,
returns a string whose characters are those of the first string
rotated 13 positions.
(Hint: You may find the % operator to be useful.)


my program thus far and its error messages can be found at
http://www.spaghettibasgetti.net/rot13error.txt

If anyone can help me, I will be eternally greatful. Thank you

------------------
I lost my toe the other day...
then I looked down at my foot and found he'd come back to me.

Guess I'll think twice about putting toes in my mouth,eh?

[Strogian]

void main()
{
cout << "Input the sentence you want translated:";
string rot13 (string normalWords);
}

Is that how you call a function in C++? I've barely used C++ at all, but if that were C, I'd wonder why you put the "string" in front of rot13.

(btw, why aren't you using the % operator like it said? =)

[uNr34l_w0m4N]

Okay, I'm a dolt. I just figured out my mistake. hehe. thank you to anyone who tried. I realised that i needed to declare my variables inside the main function, rather than out in never never land... well, that took away the errors anyhow... anyone know why is was so wrong?

------------------
I lost my toe the other day...
then I looked down at my foot and found he'd come back to me.

Guess I'll think twice about putting toes in my mouth,eh?

[uNr34l_w0m4N]

Oh, no, the errors came back as soon as i defined rot locally in the second function.

Oh, Strogian, yes, that is how you call the functions in C++... i use string because i want letters rather than numbers, although i'm beginning to think i should just use int... [integer]

and i'm not using the % operator like it said because i can't think of how i could use it effectively.

------------------
I lost my toe the other day...
then I looked down at my foot and found he'd come back to me.

Guess I'll think twice about putting toes in my mouth,eh?

[Zoma]

Time to once again over-help someone with an assignment

#include <iostream>
#include <cmath>
#include <string>

using namespace std;

string normalWords, rot;

void main()
{
cout << "Input the sentence you want translated:";
	string rot13 (string normalWords);
}

That's a bit strange. Not sure if you were trying to do,
but here's what I think you wanted to do:

#include <iostream>
#include <cmath>
#include <string>

using namespace std;

// This is a prototype.  You had yours inside the main program, which I'm not even
// sure is legal.
string rot13(string nomralWords);

void main()
{
 // Declare the variable names as local variables.
 // They were global before, meaning that they would
 // be overwritten in your function.  This is a bad
 // thing  
 string normalsWords, rot;

 cout << "Input the sentence you want translated:";

 // You need to get the stuff  
 // I'm guessing normalWords is where you wanted to
 // store the user input, and rot is where you
 // wanted to store the rotated input
 
 cin >> normalWords;
 rot = rot13(normalWords);
}

That should all be koshar, now. I'm not sure about the
type "string," as I stay away from most C++ types
If it doesn't work, I can help you use char[length] and char*

string rot13 (string normalWords)
{
	for (; 
	{
 		cin >> normalWords;
  		int i=0;
  		int over;
  		normalWords[i];
  
		if ((normalWords[i] >= 65) && (normalWords[i]<=90))
  		{
   			rot = normalWords[i] + 16;
   			if (rot > 90);
   			{
    				over = (rot - 90);
    				rot = (65-1) + over;
			}
			return rot;
	      }
	}
}

Ah, so that's where you read in normalWords. But a lot
Of that does not make sense. Why pass it in as a parameter
to the function if you're just going to read it in?
I'm guessing the function assumes that normalWords already has a value.
Also, you read in normalWords EVER iteration of the loop. But wait, the loop
returns after one character. Also, "normalWords[i];" does not make sense at
all. Maybe I'm wrong, but I don't think this will work.

My version:

string rot13(string someString)
{
	// We need a variable to use in this function
	string newString;

	// Loop through the string.
	// Not sure if strlen works on strings, so
	// you'll have to fix it if it doesn't
	for (int i = 0; i <= strlen(someString); i++)
	{
		// If the character is a valid letter, rotate it.
		// Just copy any other character
		if ((toupper(someString[i]) >= 'A') && (toupper(someString[i]) <= 'Z'))
  		{
			// If the letter is between A and M,
			// Add 13 to make it a letter between N and Z.
			// Otherwise, do the inverse.
			if (toupper(someString[i]) <= 13)
			{
				newString[i] = someString[i] + 13;
			}
			else
			{
				newString[i] = someString[i] - 13;
			}
		}
		else
		{
			newString[i] = someString[i];
		}
	}
	
	return newString;
}

Notice how I use two different variable names inside the function to avoid confusion.
I haven't tested this code, so I don't know if it will even compile. I'll
leave testing and fixing anything up to you

[uNr34l_w0m4N]

Thank you so much for your help. Along with your help and others', I finally got it working

#include <iostream>
#include <cmath>
#include <string>
using namespace std;


string rot13 (string normalWords);
void main()
{
	string normalWords;
	cout << "Input the sentence you want translated:";
	cin >> normalWords;

	cout << "\nThe rot-13 translation is: " << rot13(normalWords) << "\n\n\n";
}

string rot13 (string normalWords)
{
	string rot = normalWords;
	int  i = 0;

	for (i=0; i<normalWords.size(); i++)
	{
		rot[i]=normalWords[i];
		normalWords[i];
		if ((normalWords[i]>64) && (normalWords[i]< 91))
			rot[i] =((normalWords[i]-65+13)%26)+65;
		if ((normalWords[i]>96) && (normalWords[i]<123))
			rot[i] =((normalWords[i]-97+13)%26)+97;
    
	}
	return rot;
}

The only problem is that it doesn't recognise 2 words.... which for the moment i'm going to play naive on, i do believe... hehe. The program was due like... 2 days ago. Or maybe just yesterday. I forget. The point is is that it's late, but I hope it's not too late. hehe.

THANK YOU for everything!!!

I believe that I will probably pop in here again soon. hehe. I always enjoyed the coding forum

------------------
I lost my toe the other day...
then I looked down at my foot and found he'd come back to me.

Guess I'll think twice about putting toes in my mouth,eh?

[Conrad Song]

Should work nicely (caps only):

string rot13( string s )
{
   static const string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

   for( int i = 0; i < s.length(); ++i ) {
      s[i] = alphabet[(s[i]-'A'+13)%alphabet.length()];
   }
   return(s);
}