I just started using MS Visual C++ express to brush up on C\C++

I wrote one little sample program and it ran successfully, then every time after that i kept getting this debug assertion failed error that killed my program.

Here's my code.

#include <iostream>

using std::cout;
using std::cin;

int main(){

int int1, int2, sum; //integers 1, 2, and the sum

cout << "Hello, I will add two integers for you.";

cout << "Please enter the first number: ";
cin >> int1;

cout << "Please enter the second number: ";
cin >> int2;

sum = int1 + int2; //sum of the 2 numbers

cout << "The sum of the numbers is: " << sum;

return 0;
}

It compiles, not sure if it works, but thats not really the point. I don't know what this debug assertion failure is. Any help?