递归方法是:

static int gcd(int a, int b)
{
  if(a == 0 || b == 0) return a+b; // base case
  return gcd(b,a%b);
}

使用while循环:

static int gcd(int a, int b)
{
  while(a!=0 && b!=0) // until either one of them is 0
  {
     int c = b;
     b = a%b;
     a = c;
  }
  return a+b; // either one is 0, so return the non-zero value
}

当我返回 a+b 时，我实际上返回的是非零数字，假设其中一个是 0.

When I'm returning a+b, I'm actually returning the non-zero number assuming one of them is 0.