Problem in adding even-valued fibonacci numbers

[abdalimran]

I've written the following program..but it prints a garbage value. Why?

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int n=4000000;

    int fib;
    unsigned int sum=0;
    int a=0, b=1;

    for(int i=0; i<n; i++)
    {
         fib = a + b;

         if(fib%2==0)
            sum+=fib;

         a = b;
         b = fib;
    }

    cout<<sum;

    return 0;
}

[pheininger]

What is the maximum value for int and unsigned int in your environment?

[Cody0023]

The calculated sum is out of range for int and unsigned int in just about ANY environment. The sum is HUGEEEE