// Ask used for two integers and output GCD
//
#include <iostream>

using namespace std;


//function protopypes
int getPosInt();
int computeGCD(int , int);


int main()

{

	//declare variables
	int a , b;

	//get a and b from user
	
	a= getPosInt(); //invoke the function for a
	b = getPosInt(); //invoke to get b

	// Compute gcd
	a = computeGCD(a,b);

	// Write out gcd
	cout << "The gcd is " << a << endl;

	return 0;

}

//define function
int getPosInt()
{
	int temp; 

	do{
		cout << "Enter positive integer: ";
		cin >> temp;
	}while(temp <= 0);

	return temp;
}

int computeGCD(int a1, int b1)
{

	while(b1 != 0)
	{
		int r = a1 % b1;
		a1 = b1;
		b1 = r;
	}

	return a1;
}