GCD (Greatest Common Divisor)

Here are 3 different code for GCD, But the main Idea is always same-

//iterative gcd
int gcd ( int a, int b )
{
  int c;
  while ( b != 0 ) {
     c = b; b = a%b;  a = c;
  }
  return b;
}


//bitwise gcd
int gcd(int a, int b)
{

//actually this code is same as the previous
while(b) 
		b ^= a ^= b ^= a %= b;  //b^=a^=b^=a means swap(a,b)

return a;
}


//recursive gcd
int g_c_d(int a,int b)
{
	if(b==0)
		return a;
	else 
		return g_c_d(b,a%b);
}

Here is another short version of gcd using ternary operators:

int gcd ( int a, int b ) {
	return b ? gcd ( b, a % b ) : a ;
}