CODEWITHSUNDEEP
javastringinput
Jack
Jack

Reputation: 1

Changing input for a string variable in java

I'm trying to use string input (yes or no) as a sentinel for a loop. The loop repeats a switch statement, and at the end prompts the user with a yes or no question. Until they type 'yes' as their answer, the loop continues to receive data from the user. The problem comes from trying to receive a new value for the sentinel.

***Reviewed the comments and made some changes. Here's the updated code:

    Scanner input = new Scanner ( System.in );

    System.out.print( "Please enter a product number, 1 - 5: ");
    int product = input.nextInt();
    double sum = 0;
    boolean complete = false;

    while (!complete) {

    switch (product){
        case 1: sum = sum + 2.98;
        break;
        case 2: sum = sum + 4.50;
        break;
        case 3: sum = sum + 9.98;
        break;
        case 4: sum = sum + 4.49;
        break;
        case 5: sum = sum + 6.87;
        break;
    }
    System.out.print( "Is your order complete? Please type true or false:");
    complete = in.nextLine();
    }

All of that is working but I am still having trouble with the prompt to break the sentinel. I'm trying to get it set up to where the user types true to end the loop or false to continue it. I'm starting to think I've overlooked something. I greatly appreciate the help, thank you.

Upvotes: 0

Views: 1122

Answers (4)

davidethell
davidethell

Reputation: 12018

Two things:

1) you are redeclaring complete. The default case should just be:

default: complete = input.Stream();

2) in Java you can't compare Strings with !=. Every String is an object and by using the comparison operators you are comparing the identifiers of the objects, not the contents of the objects. Java will never see two String objects as equal unless they are two strings pointing to the same memory location. To compare the values of two strings you have to use the .equals() method such as:

while (!complete.equals("yes")) {

Or even better as a habit:

while (!"yes".equals(complete)) {

This is better because if the complete String variable were null then the first comparison would throw a null pointer exception where the second won't since the literal string "yes" will always evaluate to a not-null object.

Hope that helps.

David

Upvotes: 0

tschubach
tschubach

Reputation: 91

You are declaring complete twice. Try modifying your default case statement as:

default: complete = input.Stream()

Upvotes: 0

Jonathan M
Jonathan M

Reputation: 17451

It's griping because you declared it twice. Take off the second String declaration:

  default: complete = input.Stream(); //Not coded, but will also ask for input.

Upvotes: 0

Amir Afghani
Amir Afghani

Reputation: 38541

Change

    default: String complete = input.Stream(); //Not coded, but will also ask for input.

to

    default: complete = input.Stream(); //Not coded, but will also ask for input.

You're redeclaring a String, which is not what you want. And follow the advice given of using .equals, not == for Strings or other reference types.

Upvotes: 2

Related Questions