C Program for Basic Euclidean algorithms?

Here we will see the Euclidean algorithm to find the GCD of two numbers. The GCD (Greatest Common Divisor) can easily be found using Euclidean algorithm. There are two different approach. One is iterative, another one is recursive. Here we are going to use the recursive Euclidean algorithm.

Algorithm

EuclideanAlgorithm(a, b)

begin
   if a is 0, then
      return b
   end if
   return gcd(b mod a, a)
end

Example

 Live Demo

#include<iostream>
using namespace std;
int euclideanAlgorithm(int a, int b) {
   if (a == 0)
      return b;
   return euclideanAlgorithm(b%a, a);
}
main() {
   int a, b;
   cout << "Enter two numbers: ";
   cin >> a >> b;
   cout << "GCD " << euclideanAlgorithm(a, b);
}

Output

Enter two numbers: 12 16
GCD 4