GCD(Euclidean Algorithm)

/*
	GCD stands for greatest common divisor.
	Here we're using Euclidean algorithm to find GCD.
	This alorithm states that GCD(a,b) = GCD(b%a,a)
	So we created a function that calls another recursive function
	which works as the same.
	inside findGCD(int num1, int num2) we keep on calling findGCD(num2%num1,num1)
	until we have num1 as 0
	as soon as we get 0 in num1 we're returning num2
	
	Time complexity = O(log x)  where x = min(num1,num2) 
*/

#include<bits/stdc++.h>
using namespace std;		
int findGCD(int num1=1, int num2=1) { //considring default value as 1
	if(num1==0)
		return num2;
	return findGCD(num2%num1,num1);
}
		
int main() {
	
	//Taking input
	int num1,num2;
	cout<<"Enter the first number : ";
	cin>>num1;
	cout<<"Enter the second number : ";
	cin>>num2;
	
	cout<<"GCD = "<<findGCD(num1,num2)<<endl;
	
	return 0;
}