Question

Write a JAVA program that repeatedly prompts your user for a number, uses a recursive function to calculate the product of that number times three (3), and displays the product. Select a sentinel value that allows your user to quit. Do NOT use the multiplication operator (*) in your proposed solution.

Answer 1

// Scanner class is imported to receive user input

import java.util.Scanner;

// class Solution is defined

public class Solution{

// recursive function to calculate

// multiplication of two numbers

// the second number is initialised to 3

// it return the product

public static int product(int x, int y)

{

// first it check if 3 is not 0

// then it uses repetitive addition to get the product

// it continues till 3 becomes 0

if (y != 0)

return (x + product(x, y - 1));

}

// main method to begin program execution

public static void main (String[] args)

{

// Scanner object scan is initialize to receive input

// via keyboard

Scanner scan = new Scanner(System.in);

// prompt is display to user to enter number

System.out.println("Enter your number to multiply: ");

// user input is assigned to x

int x = scan.nextInt();

// 3 is assigned to y which specify the number of times to multiply

int y = 3;

// while loop that continue to receive user input as long as it is not -1

while(x != -1){

// The result of the product is displayed

System.out.println(product(x, y));

// prompt is display to user to enter number

System.out.println("Enter your number to multiply: ");

// user input is assigned to x

x = scan.nextInt();

}

}

}

Step-by-step explanation:

The program is written in Java. An image of program output when the code is executed is attached.

A Scanner class is imported that allow program to read input. Then the product method is defined that compute the product of a number3 times using repetitive addition.

Then the method product is called inside the main method where the user is asked to continue input a number as long as the sentinel value (-1) is not entered.