How to loop a menu if wrong selection occurred

Question

I am trying to loop a menu when the user insert wrong choice:

public static void main(String[] args) {

    Scanner YourChoice = new Scanner(System.in);

    System.out.println("+-------------------------+");
    System.out.println("|        Welcome          |");
    System.out.println("|    To this program      |");
    System.out.println("+-------------------------+");
    System.out.println();

    System.out.println("Please Choose your preference: ");
    System.out.println();
    System.out.println("Press 1 - Test1");
    System.out.println("Press 2 - Test2");
    System.out.println("Press 3 - Test3");
    System.out.println("Press 0 - Exit");


    System.out.println();
    System.out.print("Your Choice is: ");
    int CHOICE = YourChoice.nextInt();



    if (CHOICE == 1) {
        System.out.println("You want Test1"); 
    }
    else if (CHOICE == 2) {
        System.out.println("You want Test2"); 
    }
    else if (CHOICE == 3) {
        System.out.println("You want Test3"); 
    }
    else if (CHOICE == 0) {
        System.out.println("You want Exit"); 
    }
    else {
        System.out.println("Wrong Input, please try again");

    }

What I want is, if a user inserted wrong number, then the menu should start again, until the user enters a correct value (0 to 3). I am not sure where and how to put the while loop, Could you please clarify it?

Answer 1

Use only while and switch-case in your program.

You can try the below code. It runs successfully.

import java.util.*;
public class Main
{
    public static void main(String[] args) {

        System.out.println("+-------------------------+");
        System.out.println("|        Welcome          |");
        System.out.println("|    To this program      |");
        System.out.println("+-------------------------+");
        System.out.println();

        Scanner yourChoice = new Scanner(System.in);
        int choice ; 
        boolean tryAgain = true;

        while (tryAgain){

            System.out.println("Please Choose your preference: ");
            System.out.println();
            System.out.println("Press 1 - Test1");
            System.out.println("Press 2 - Test2");
            System.out.println("Press 3 - Test3");
            System.out.println("Press 0 - Exit");
            System.out.println();
            choice = yourChoice.nextInt();
            System.out.print("\nYour Choice is : " +choice + "\n");

            switch(choice){
                case 1 :
                    System.out.println("You want Test1");
                    tryAgain = false;
                    break;
                case 2 :
                    System.out.println("You want Test2");
                    tryAgain = false;
                    break;
                case 3 :
                    System.out.println("You want Test3");
                    tryAgain = false;
                    break;
                case 0 :
                    System.out.println("You want exit");
                    tryAgain = false;
                    break;
                default :
                    System.out.println("Wrong Input, please try again");
            }

        }

    }
}