Hello everybody, I'm pretty much a beginner at using C, so my problem shouldn't be too difficult for you to solve, I hope. I wrote this program to sum all the even numbers in the fibonacci sequence below 4 million:

Code:
#include <stdio.h>

int main()
{
    int current = 0;
    int prev = 1;
    int prev2 = 0;
    int sum = 0;
    do {
          current += (prev + prev2);
          prev2 = prev;
          prev = current;
          if (current%2==0){
             sum += current;
             }          
       } while (current < 4000000);
    printf("The answer is %d.", sum);
    getchar();
    return 0;
}
When I run this program, it returns "The answer is 0.", and I can't figure out why. Any ideas?