Iterative Constructs in Java

Chapter 9

Iterative Constructs in Java

Class 10 - Logix Kips ICSE Computer Applications with BlueJ

Share with a Friend

Java Program: Menu Driven Program - Buzz Number and GCD Checker

27. Write a menu driven program to accept a number from the user and check whether it is a BUZZ number or to accept any two numbers and to print the GCD of them.

(1). A BUZZ number is the number which either ends with 7 or is divisible by 7.

(2). GCD (Greatest Common Divisor) of two integers is calculated by continued division method. Divide the larger number by the smaller; the remainder then divides the previous divisor. The process is repeated till the remainder is zero. The divisor then results the GCD.

Program Title: Buzz Number and GCD Checker

Java

import java.util.Scanner;
 
public class BuzzGCDMenu {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 
        System.out.println("MENU");
        System.out.println("1. Check Buzz Number");
        System.out.println("2. Find GCD of Two Numbers");
        System.out.print("Enter your choice: ");
        int choice = sc.nextInt();
 
        switch (choice) {
            case 1:
                // Check Buzz number
                System.out.print("Enter a number: ");
                int num = sc.nextInt();
 
                if (num % 10 == 7 || num % 7 == 0) {
                    System.out.println(num + " is a Buzz Number.");
                } else {
                    System.out.println(num + " is NOT a Buzz Number.");
                }
                break;
 
            case 2:
                // Compute GCD
                System.out.print("Enter first number: ");
                int a = sc.nextInt();
                System.out.print("Enter second number: ");
                int b = sc.nextInt();
 
                int x = a, y = b;
 
                while (y != 0) {
                    int remainder = x % y;
                    x = y;
                    y = remainder;
                }
 
                System.out.println("GCD of " + a + " and " + b + " is: " + x);
                break;
 
            default:
                System.out.println("Invalid choice! Please select 1 or 2.");
        }
 
        sc.close();
    }
}

Output

Sample Output 1 (Buzz Number)
MENU
1. Check Buzz Number
2. Find GCD of Two Numbers
Enter your choice: 1
Enter a number: 35
35 is a Buzz Number.

Sample Output 2 (GCD)
MENU
1. Check Buzz Number
2. Find GCD of Two Numbers
Enter your choice: 2
Enter first number: 48
Enter second number: 180
GCD of 48 and 180 is: 12

📝 Explanation

1. Buzz Number:

A number is a Buzz number if it ends with 7 (num % 10 == 7)
OR is divisible by 7 (num % 7 == 0).

2. GCD (Euclidean Algorithm):

Continuously divide the larger number by the smaller number.
Replace the larger number with the smaller, and the smaller with the remainder.
Repeat until remainder = 0.
The divisor at that point is the GCD.

3. Switch-case is used for menu selection.