/******************************************************

** Name: 

** Filename: gcd.cpp

** Project #: Deitel & Deitel 3.45

** Project Description: The greatest common divisor of integers x
   and y is the largest integer that evenly divides both x and y. 
   Write a recursive function gcd that returns the greatest common
   divisor of x and y. The gcd of x and y is defined recursively as
   follows: If y is equal to 0, then gcd(x,y) is x; otherwise gcd(x,y)
   is gcd(y, x % y ), where % is the modulus operator.

** Output: Greatest common diviser of the two input integers

** Input: Two integers

** Algorithm: Print program purpose
              Instruct user to input two integers
			  Use two input integers in the recursive gcd function
				If y == 0, then gcd(x,y) is x
				Else gcd(x,y) is gcd(y, x % y)

			  Return the gcd of the two input integers
			  End program

******************************************************/

// Include files
#include <iostream>  // used for cin, cout
#include <conio.h>
using namespace std;

// Global Type Declarations

// Function Prototypes
void instruct (void);
void pause ();
int gcd ( int, int );

//Global Variables - should not be used without good reason.

int main ()
{
	 // Declaration section
	int int1,
		int2;
	 
	 // Executable section
	 instruct ();

	cout << "Enter first integer: ";
	cin >> int1 ;
    cout << "Enter second integer: ";
	cin >> int2;
	cout << "\nThe greatest common divisor of " << int1 << " and "
		 << int2 << " is " << gcd(int1,int2) << endl;


	 pause ();
	 return 0;
}

int gcd ( int x, int y )
{

		if ( y == 0 )
			return x;
		else 
			return gcd( y, x % y );  
		
}
void instruct (void)
{
	  // Declaration section
	cout << "This program will take two numbers that are input and\n"
		 << "return the greatest common divisor of the two numbers.\n"
		 << "______________________________________________________\n"
		 << endl;
	  // Executable section
}

void pause ()
{
    // Declaration section

    // Executable section
    cout << "\nPress any key to continue...";
    getch();
    cout << "\r";
    cout << "                            ";
    cout << "\r";
}


/*
Program Output

This program will take two numbers that are input and
return the greatest common divisor of the two numbers.
______________________________________________________

Enter first integer: 75
Enter second integer: 25

The greatest common divisor of 75 and 25 is 25

Press any key to continue...

*/