C++ Encryption, Loop on each character

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

Program:      CeaserShift

File:         ceaser.cpp

Function:     Main (complete program listing in this file)
              Change (Adds rot onto the chars)

Description:  CeaserShift Bruter

Author:       Simon Morris

Environment:  Dev C++ version 4.9.9.2, 486/66 1024mb RAM, WindowsXP

Notes:        None as yet

Revisions:    1.00  05/10/2006 (jl) First release

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

// Initial Includes
#include <iostream>
#include <stdio.h>
#include <string>
using namespace std;

string change(string input, int rot);

int main() {
    string text;
    cout << "Enter some text: ";
    std::getline(std::cin, text);
    string newtext;
    int rot;
    rot = 0;
    for(rot=0;rot<=26; rot++) {
       newtext = change(text, rot);
       cout << "Rot: " << rot << newtext << endl << endl;
    }
    system("PAUSE");
    return 0;
}



string change(string input, int rot) {
       int chr = 0;
       string current;
       string output;
       while (chr < input.length()) {
             if (input[chr] >= 'a' && input[chr] <= 'z') {
                current = input[chr] - 'a' + 'A' + rot;
                } else {
                current = input[chr];
             }
             output = output + current;
             chr ++;      
       }
       return output;      
}

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

Program:      CaesarEncrypt

File:         caesar.cpp

Function:     Main (complete program listing in this file)
              Change (Adds rot onto the chars)
              Brute (Runs throught all 26 rots)

Description:  CaesarShift Bruter

Author:       Simon Morris

Environment:  Dev C++ version 4.9.9.2, 486/66 1024mb RAM, WindowsXP
			  Notpad2.exe 1.0.12, 224mb RAM, WindowsXP

Notes:        None as yet

Revisions:    1.00  05/10/2006 (jl) First release
              1.01  05/10/2006 (jl) Improvement on alphabet error
              1.10  06/10/2006 (jl) Encryptor
              1.11  06/10/2006 (jl) Spelling Error

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

// Initial Includes
#include <iostream>
#include <stdio.h>
#include <string>
using namespace std;

string change(string input, int rot);
int brute (string inputLoop);
string caesarEncrypt;
int main() {
    string text;
    string eText;
    int uRot;
    int cinReturn;
    int x = 1;
    while (x > 0) {
	// Message Loop
	   cout << "*** Main Menu ***\nPress Corresponding number and press enter\n\n1. Brute Force Caesar Cipher\n2. Encrypt Caeser Cipher\n3. Exit\n";
	   cin >> cinReturn;
	   switch (cinReturn) {
			case (1):
				cout << "Enter you encrypted text: ";
				std::getline(std::cin, text);
				brute(text);
				break;
			case (2):
				cout << "Enter text to be encrypted";
				std::getline(std::cin, eText);
				cout << "Enter rot value: ";
				cin >> uRot;
				cout << "Your encrypted text is: " << change (eText, uRot) << endl;
				break;
			case (3):
				cout << "Exitting...";
				x++; // End Loop
				break;
			default:
				cout << "Unrecognised input";
		}

    }
    system("PAUSE");
    return 0;
}

int brute (string input) {
       string newtext;   
       int rot;
       for(rot=0;rot<=26; rot++) {
          newtext = change(input, rot);
          cout << "Rot " << rot << ": " << newtext << endl;
       }
       return 0;      
}

string change(string inputLoop, int rot) {
       int chr = 0;
       string current;
       string output;
       while (chr < inputLoop.length()) {
             if (inputLoop[chr] >= 'a' && inputLoop[chr] <= 'z') {
                current = inputLoop[chr] - 'a' + 'A' + rot;
                if (current[0] > 'Z') {
                   current[0] = current[0] - 'Z' + 'A';
                }
                } else {
                current = inputLoop[chr];
             }
             output = output + current;
             chr ++;      
       }
       return output;      
}