Greatest common divider

gcd.cpp

#include <iostream>
using namespace std;

int gcd(int a, int b) {
  while (a != b) {
    if (a > b) {
      a = a - b;
    } else {
      b = b - a;
    }
  }
  return a;
}

int main() {
  int a, b;

  cout << "a = ";
  cin >> a;
  cout << "b = ";
  cin >> b;

  cout << "GCD ( " << a << ", " << b << " ) = " << gcd(a, b) << endl;
  system("pause >> void");

  return 0;
}