project euler problem #2

p2.cpp

#include <iostream>
using namespace std;

int fib(int _n){
  if(_n <= 0)
    return 0;
  else if(_n == 1)
    return 1;
  else if(_n == 2)
    return 2;
  else
    return fib(_n - 1) + fib(_n - 2);
}

int main()
{
  int sum = 0;
  int f = 0;
  int i = 0;
  while((f = fib(i)) < 4000000){
    if(f % 2 == 0)
      sum += f;
    i++;
  }

  cout << "sum=" << sum << endl;
  return 1;
}