Ytukyg

I have a code that requests input from the user, it runs just fine however I want to re-prompt the user to input a valid response instead of continuing to run.

Here's the code:

import java.io.*;

public class SkiLodge {



    public static void main(String args) throws Exception

    {



        InputStreamReader ui = new InputStreamReader (System.in);

        BufferedReader inputReader = new BufferedReader(ui);



        System.out.println("Select Membership Type: (Gold/Silver/Bronze)");

        String membership = inputReader.readLine();



        double x = 0d;



        if (membership.equals("Gold"))

            System.out.println("Gold Membership Selected: £" + (x = 750));

        else if (membership.equals("Silver"))

            System.out.println("Silver Membership Selected: £" + (x = 450));

        else if (membership.equals("Bronze"))

            System.out.println("Bronze Membership Selected: £" + (x = 250));

        else System.out.println("Invalid Membership");







        System.out.println("Do you require snow tyre rental? (yes/no)");

        String tyreRental = inputReader.readLine();





        if (tyreRental.equals("yes"))

            System.out.println("The total so far with tyre rental: £" + (x = x * 1.1));

        else if (tyreRental.equals("no"))

            System.out.println("The total so far without tyre rental: £" + x);

        else System.out.println("Invalid response");



        System.out.println("Would you like to reserve parking? (yes/no)");

        String parking = inputReader.readLine();



        if (parking.equals("yes"))

        System.out.println("Membership total: £" + (x = x * 1.08));

        else if (parking.equals("no"))

        System.out.println("Membership total: £" + x);

        else System.out.println("Invalid response");

    }



}

So for example if the user inputs Gold, the program prints out 750, if not then it prints out invalid membership and asks for a valid one.

Same goes for the following questions, so the program only accepts yes and no as valid responses.

Thanks in advance

You can use a do-while loop.

do{

    //Some code here



    //if block

    else { // last else block.

         System.out.println("Invalid Membership");

         continue;  // This will skip the rest of the code and move again to the beginning of the while loop.

    }



    //More code



    break; // If the condition was correct, then you need not worry. This statement will pull out of the loop.

}while(true);

You can modify this to put a do-while loop any where you have such requirement.

This would make your whole code to:

public static void main(String args) throws Exception

{



    InputStreamReader ui = new InputStreamReader (System.in);

    BufferedReader inputReader = new BufferedReader(ui);

    String membership, tyreRental,parking;

    double x = 0d;

    do

    {

        System.out.println("Select Membership Type: (Gold/Silver/Bronze)");

        membership = inputReader.readLine();



        if (membership.equals("Gold"))

            System.out.println("Gold Membership Selected: £" + (x = 750));

        else if (membership.equals("Silver"))

            System.out.println("Silver Membership Selected: £" + (x = 450));

        else if (membership.equals("Bronze"))

            System.out.println("Bronze Membership Selected: £" + (x = 250));

        else{

            System.out.println("Invalid Membership");

            continue;

        }

        break;

    }while(true);



    do{

        System.out.println("Do you require snow tyre rental? (yes/no)");

        tyreRental = inputReader.readLine();



        if (tyreRental.equals("yes"))

            System.out.println("The total so far with tyre rental: £" + (x = x * 1.1));

        else if (tyreRental.equals("no"))

            System.out.println("The total so far without tyre rental: £" + x);

        else{ System.out.println("Invalid response"); continue;}

        break;

    }while(true);



    do{

        System.out.println("Would you like to reserve parking? (yes/no)");

        parking = inputReader.readLine();



        if (parking.equals("yes"))

            System.out.println("Membership total: £" + (x = x * 1.08));

        else if (parking.equals("no"))

            System.out.println("Membership total: £" + x);

        else {System.out.println("Invalid response"); continue;}

        break;

    }while(true);

}

Unfortunately there's no really elegant way of avoiding two input statements in this situation. There are various ways of doing this but I find the neatest is the most straightforward:

System.out.println("Select Membership Type: (Gold/Silver/Bronze)");

String membership = inputReader.readLine();

while (!membership.matches("Gold|Silver|Bronze")) {

    System.out.println("Illegal membership Type; please enter one of Gold, Silver or Bronze");

    membership = inputReader.readLine();

}

Ideally you would encapsulate some of that logic so that you weren't repeating it in several places. That will make your code a bit neater. For example:

enum Membership {

    GOLD(750),

    SILVER(450),

    BRONZE(250);



    private int value;



    Membership(int value) {

        this.value = value;

    }



    public int getValue() {

        return value;

    }



    public static Membership getByName(String name) {

        for (Membership membership: values())

            if (name.toUpperCase().equals(membership.name))

                return membership;

        return null;

    }

}



System.out.println("Select membership type: " + Membership.values());

Membership membership = Membership.getByName(inputReader.readLine());

while (membership == null) {

    System.out.println("Illegal membership Type; enter one of " + Membership.values());

    membership = Membership.getByName(inputReader.readLine());

}

int x = membership.getValue();