Question

Using the code below as a template, write a program that asks the user to enter two integers, and finds and prints their greatest common denominator (GCD) in Java!

package cp213;

import java.util.Scanner;

public class Lab01 {

    /**
     * @param a
     * @param b
     * @return
     */
    public static int gcd(int a, int b) {

        // your code here

    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int a = 0;
        int b = 0;
        int c = 0;

        // Read an integer from the keyboard.
        System.out.print("Enter a (0 to quit): ");
        a = keyboard.nextInt();

        // your code here

        // gcd function call
        c = Lab01.gcd( a, b );

        // your code here

    }

}

Answer 1

package cp213;

import java.util.Scanner;

public class Lab01 {

    /**
     * @param a
     * @param b
     * @return
     */
    public static int gcd(int a, int b) {
        if (a == 0 || b == 0)
            return 0;
        else if (a == b)
            return a;
        else if (a > b)
            return gcd(a - b, b);
        else
            return gcd(a, b - a);
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int a = 0;
        int b = 0;
        int c = 0;

        while (true) {
            // Read an integer from the keyboard.
            System.out.print("Enter a number(0 to quit): ");
            a = keyboard.nextInt();
            if (a == 0) break;
            System.out.print("Enter another number: ");
            b = keyboard.nextInt();

            // gcd function call
            c = Lab01.gcd(a, b);

            System.out.println("GCD of " + a + " and " + b + " is " + c + "\n");
        }
    }
}