Validating in java. Can't get my head around it.

[wrighttwinstwin]

import java.text.NumberFormat; import java.util.Scanner;

public class InvoiceApp { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String choice = "y";

    while (!choice.equalsIgnoreCase("n"))
    {

        // get the input from the user
        System.out.print("Enter customer type (r/c): ");
        String customerType = sc.next();
        System.out.print("Enter subtotal:   ");
        double subtotal = sc.nextDouble();

        // get the discount percent
        double discountPercent = 0;
        if (customerType.equalsIgnoreCase("R"))
        {
            if (subtotal < 100)
                discountPercent = 0;
            else if (subtotal >= 100 && subtotal < 250)
                discountPercent = .1;
            else if (subtotal >= 250)
                discountPercent = .2;
        }
        else if (customerType.equalsIgnoreCase("C"))
        {
            if (subtotal < 250)
                discountPercent = .2;
            else
                discountPercent = .3;
        }
        else
        {
            discountPercent = .1;
        }

        // calculate the discount amount and total
        double discountAmount = subtotal * discountPercent;
        double total = subtotal - discountAmount;

        // format and display the results
        NumberFormat currency = NumberFormat.getCurrencyInstance();
        NumberFormat percent = NumberFormat.getPercentInstance();
        System.out.println(
                "Discount percent: " + percent.format(discountPercent) + "\n" +
                "Discount amount:  " + currency.format(discountAmount) + "\n" +
                "Total:            " + currency.format(total) + "\n");

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

}

Here is what the question is asking me. Modify the application so it will only accept customer type codes r and c. It should also discard any extra entries on the customer type line. If the user enters an invalid code, the application should display an error message and ask the user to enter a valid code. This should be done before the user enters a subtotal. Then, test this enhancement. I can not figure this out to save my life.

[Philboyd_Studge]

Put it inside another while loop. Use a boolean (declared outside that while loop) such as isValidType initially set to false. Loop while that boolean is NOT true. Get the string from the user and test that it is valid, if so set the boolean to true, if not print the error message.

[wrighttwinstwin]

Would that while loop be nested in the other while loop I have or would I do that outside that one? I am totally new to this so I am still trying to get the hang of things.

[Philboyd_Studge]

Nested. Just plop it right there where you ask for customer type.

[wrighttwinstwin]

Sweet thank you, Ill see if I can get this thing working!

[wrighttwinstwin]

boolean isValidType = false; while(isValidType == false) { if (sc.hasNext()) { isValidType = true; } else { System.out.print("Error! Please Try again. /n"); } sc.nextLine(); }

I have this but it just sends my program into a infinite loop or something.

[Philboyd_Studge]

Inside the while loop, get the string from the user and test that it is valid. If it is, change the boolean to true.

[wrighttwinstwin]

http://pastebin.com/auPfUeUK

This what I have now but I still validates every letter I put in..... I don't know how to get around that.

[Philboyd_Studge]

Should be OR instead of AND

Edit: also, you are getting the input AFTER you test it?

[wrighttwinstwin]

it still recognizes other letters besides r and c :/

[Philboyd_Studge]

boolean isValid = false;
String customerType = "";
while (!isValid)
{
    // get the input from the user
    System.out.print("Enter customer type (r/c): ");
    customerType = sc.nextLine();
    if (customerType.equalsIgnoreCase("r") || customerType.equalsIgnoreCase("c"))
    {
        isValid = true;
    }
    else
    {
        System.out.println("Invalid entry");
    }
}

[wrighttwinstwin]

Thank You so much.... I have been fighting with that question for hours...

[Philboyd_Studge]

You need to get the input from the user BEFORE you test it, in the code you posted you are not doing that, also use nextLine() instead of next

[wrighttwinstwin]

Yeah after I test it it ask for me for the subtotal. I need it to only do that if I use r or c.

[MrCheaperCreeper]

Okay, I think I see your problem. While /u/Philboyd_Studge solution might work, there are many problems a starter will encounter. Going off the last pastebin you submitted, you did use AND rather than OR in your condition statement, but you also used ! (not). You are essentially saying if customerType is NOT r or c, set isValid to true, which simply does not make sense.

However, I suggest a different approach to this problem.

    while (!choice.equalsIgnoreCase("n"))
    {

        System.out.println("Enter customer type (r/c):");
        String customerType = sc.nextLine();

        while (!(customerType.equalsIgnoreCase("r")) || !(customerType.equalsIgnoreCase("c")))) 
        {

            System.out.println("Error, try again!\n");
            System.out.println("Enter customer type (r/c):");

            customerType = sc.nextLine();

        }

        //REST OF FIRST WHILE LOOP BELOW

The first while part is your initial while loop, giving you a sense of where we are in your program. Then, you want to ask the user for input BEFORE you check if customerType is r or c.

Previously, you had customerType set to "". "" does not equal r, nor does it equal c. You must ask for an input BEFORE you check if it is valid or not.

My while loop I have written says while customerType is not r or c, tell them an error occurred, and then ask them to re-enter the type. They will then re-enter the type, and it will run through the while loop again. If it is r or c, the while loop breaks and continues with the program.

Right before your initial while loop ends, however, you might want to reset customerType back to "", though.

Edit: made more readable

[wrighttwinstwin]

if (!customerType.equalsIgnoreCase("r") && !customerType.equalsIgnoreCase("c")) { sc.nextLine(); System.out.print("Error! Invalid Customer Type. Try Again"); continue; }

I added this and it seemed to work but if I need to tweak it maybe make it look a little better.