cryptic message help

[fluffy]

This is suppose to take in a message and return it in upper and lower cade cryptic message . there should be the use of bool islower(char) abd bool isupper(char)

This is what i have so far:

#include <cstdlib>
#include <iostream>
#include <cctype>
using namespace std;

int main()
{
    int shift;
    string message;
    string cript;
    char curChar;
    int curCode;
    cout<<"shift 0-25 :"<<endl;
    cin>>shift;
    
    getline(cin,message);
    cin.ignore();
    
    cout<<"Plain text :"<<endl;           
    getline(cin,message);
    
    for (int i=0; i< message.length(); i++)
    {
       curChar = message.at(i); 
       if( isalpha(curChar))
        {
          curChar = message.at(i);
          curCode= int(curChar);
    
          cout<< curChar <<"______________________"<< curCode <<endl;
    
        }
    }
    cout<<"the message is"<<message<<endl;
    
    system("PAUSE");
    return EXIT_SUCCESS;
    }