Starting Java

[Richard Maxwell]

Hello

I am teaching myself Java, I am brand new to Java, my friend recommend buy a book from amazon.

I am struck where it says I am suppose to change case.
Here is what i like to do. when a user enter a number it calculate and display and it ask do you want to continue I want the user to choose either lower or upper case Y or y or N or n.

Any help would be great

[Kemal Sokolovic]

Welcome to the Ranch!

In order to get the most out of people in this community, you need to TellTheDetails, possibly with some code snippet that reflects what you are trying to do. Currently, I'm not clear on what the issue is exactly, but if you want to check for the user input ignoring the case (Y or y, or whatever) then you might want to check String#equalsIgnoreCase(String) method.

[Richard Maxwell]

Thank you kemal for response

Here is the code

import java.util.Scanner;

public class InvoiceApp
{
    public static void main(String[] args)
    {
        // welcome the user to the program
        System.out.println(" Invoice Total Calculator");
        System.out.println();  // print a blank line

        // create a Scanner object named sc
        Scanner sc = new Scanner(System.in);

        // perform invoice calculations until choice isn't equal to "y" or "Y"
        String choice = "y";
        while (choice.equalsIgnoreCase("y"))
        {
            // get the invoice subtotal from the user
            System.out.print("Enter subtotal:   ");
            double subtotal = sc.nextDouble();

            // calculate the discount amount and total
            double discountPercent= 0.0;
            if (subtotal >= 200)
                discountPercent = .2;
            else if (subtotal >= 100)
                discountPercent = .1;
            else
                discountPercent = 0.0;

            double discountAmount = subtotal * discountPercent;
            double total = subtotal - discountAmount;

            // display the discount amount and total
            String message = "Discount percent: " + discountPercent + "\n"
                           + "Discount amount:  " + discountAmount + "\n"
                           + "Invoice total:    " + total + "\n";
            System.out.println(message);

            // see if the user wants to continue
            System.out.print("Continue? (y/n): ");
            choice = sc.next();
            System.out.println();
        }
    }
}

As you can see the program will end by pressing any key, but I want program to end only when a user enter N or n

I am not sure if i should use not operator ( ! ) Or equalsIsIgnoreCase and I am not sure how to use it.

[Jayesh A Lalwani]

Richard,

Please use code tags while posting code. It makes it easier for others to read. I have done it for you this time

[Jayesh A Lalwani]

You can use the or operator|| to check for 2 conditions. a||b is true if either one of them is true

[Kemal Sokolovic]

As you can see the program will end by pressing any key, but I want program to end only when a user enter N or n

Then you should think it this way: Repeat everything if the user did not enter N or n (in other words, the user can enter anything else). This is where the negation operation would be suitable.

[Richard Maxwell]

Hey guys thank you kemal and Jayesh as per your suggestion I made the changes now it works.


String choice = "y";
String choices ="n";

while (!choice.equalsIgnoreCase("y") == (!choices.equalsIgnoreCase("n")))

[Campbell Ritchie]

Richard Maxwell wrote: . . . while (!choice.equalsIgnoreCase("y") == (!choices.equalsIgnoreCase("n")))

I suggest you work out what that means. It looks like a tautology to me.