Question

Write a Java program that reads a whole number on the keyboard and obtains and displays twice and triple that number on the screen

Answer 1

import java.util.Scanner;

public class WholeNumber {

        public static void main(String[] args) {
                
                int wholeNumber;
                Scanner sc = new Scanner(System.in);
                
                // reading whole number until valid entry
                while(true) {
                        System.out.print("Enter a whole number : ");
                        wholeNumber = sc.nextInt();
                        // if number is valid then break
                        if(wholeNumber >= 0)
                                break;
                        System.out.println(wholeNumber + " is not a whole number");
                }
                
                // doubling the number 
                int twice = 2 * wholeNumber ;
                System.out.println("Twice of "+wholeNumber+"  = "+twice);
                
                // tripling the number
                int triple = 3 * wholeNumber; 
                System.out.println("Triple of "+wholeNumber+" = "+triple);
                
                sc.close();
        }

}

Code  

Output