Natural numbers on c program

#include 

int gcd (int a, int b) 

{

  int temp;

  while (b != 0) 

{

    temp = a % b;

    a = b;

    b = temp;

  }

  return(a);

}

int main () 

{

  int x, y;

  cout << "Enter two natural numbers: ";

  cin >> x >> y;

  cout << "gcd(" << x << ", " << y << ") = " << gcd(x,y) << endl;

  return(0);

}