C++ Leap Year program with "variable is being used without being initialized" and always return true problem

When I run it, it shows "Run-Time Check Failure #3 - The variable 'carryOn' is being used without being initialized."
And I found out no matter I input a leap year or not a leap year, it always return it "is a leap year" I'm new to C++ so please help me
#include <iostream>
#include <cstdlib>
using namespace std;

int getYear();
bool isLeap(int year);
char moreData();

int main()
{
int year;
char carryOn='y';

while(carryOn=='y'||carryOn=='Y'){
year=getYear();

if(isLeap(year)){
cout<<" is a leap year\n";
}else{
cout<<" is not a leap year\n";
}
carryOn=moreData();
}
system("pause");
}
int getYear(){
int year;
cout<<"Enter a year: ";
cin>>year;
return year;
}
bool isLeap(int year){
if(year%4==0){
if (year%100!=0){
return(true);
}else if (year%400==0){
return(false);
}
return isLeap;
}}
char moreData(){
char carryOn;
cout<<"Do you want to enter more data? (y/n) ";
return carryOn;
}

Here is the requirements for this program:

Create a program that prompts the user to enter a year and then determines whether it is a leap year. The program should have a loop and continue while the user enters the 鈥榶鈥?character.

Write three functions according to the following descriptions:

getYear has no formal parameters, ask the user to enter a year, and returns an integer value that is assigned to the integer variable year.

isLeap has an integer formal parameter year, determines whether the year is a leap year, and returns the Boolean value true if the year is a leap year and false if it is not. A year is a leap year if it is divisible by 4, but is not divisible by100 except when divisble by 400 (The year 2000 was a leap year).

moreData has no formal parameters and returns a character value.

I think there are two problems in your code.

First, the warning is talking about this function
char moreData(){
char carryOn;
cout<<"Do you want to enter more data? (y/n) ";
return carryOn;
}
Notice your 'carryOn' variable is return without being assigned anything. I guess you intend to have something like this?
char moreData(){
char carryOn;
cout<<"Do you want to enter more data? (y/n) ";
cin >> carryOn;
return carryOn;
}

Your check for leap year is also wrong. Try this (I haven't tested it though).
bool isLeap(int year){
if ( year % 4 == 0 && ( year % 100 != 0 || year % 400 == 0 ) ) {
return true;
}
else {
return false;
}
}

hi,
i did some modification in this program..just verify.
#include <iostream>
#include <cstdlib>
using namespace std;

int getYear();
bool isLeap(int year);
char moreData();

int main()
{
int year;
char carryOn='y';

while(carryOn=='y'||carryOn=='Y')
{
year=getYear();

if( isLeap(year) )
cout<<" is a leap year\n";

else
cout<<" is not a leap year\n";

carryOn=moreData();
}
system("pause");
return 0;
}

int getYear(){
int year;
cout<<"Enter a year: ";
cin>>year;
return year;
}

bool isLeap(int year){
if(year%4==0){

if (year%100!=0)
return(true);

else if (year%400==0)
return(true);
}
else
return false;
}

char moreData(){
char carryOn;
cout<<"Do you want to enter more data? (y/n) ";
cin>>carryOn;
return carryOn;
}