How to allow specific letters only?

[ctmarco3]

Hi, I am looking for a simple way to require an entry of either "a" "b" or "c"
Or an "x" (to exit)
If they enter anything else it should throw up a simple error "Example Error Invalid entry. Try again"
discard any possible extra entries if any are present and prompt for reentry
It needs to be a static method that I can reuse anytime.

[Junky]

I've heard of this thing called an if statement.

[Solarsonic]

char c;
if (c=='x')
System.exit(0);

Etc.

[Junky]

[cough]
syntax
[/cough]

Stoopid minimal length

[ctmarco3]

Hah ok that may be simple enough to get me going thanks guys. I will be back. :)

[Solarsonic]

[cough]
syntax
[/cough]

Stoopid minimal length

My bad, I wrote that without looking :p

[ctmarco3]

Ok maybe not, I do kind of understand if else statements for numbers, I guess I don't quite for letters though. Here is my (rough) code so far. I want to change the y/n input so instead it just runs over and over until an "x" is entered. Do I take the while statement out altogether? and for my "getValidCustomerType" method I am not even sure how to start it.
main code:

import java.text.*;
import java.util.*;

public class ValidatedInvoiceApp		{
    public static void main(String[] args)	    {
		//call method
		 		MarcoHeading.getHeading("Assignment 4");

		         // display a welcome message
         System.out.println("  Welcome to the Invoice Application\n");
        Scanner sc = new Scanner(System.in);
        String choice = "y";
		//not sure how to start this part?
        while (choice.equalsIgnoreCase("y"))	{
        	
        	// get the input from the user
			
			//call method to validate customer type 
        	String customerType = getValidCustomerType(sc,
        		"  Enter customer type <C/R/T> or X to Exit:  ");
        		//call method to valdiate invoice amount
        	double discountAmount = getValidSubtotal(sc,
        	"		      Enter Invoice Amount:  ",0, 10000);
        	double subtotal = sc.nextDouble();

        	// call the method for getting the discount percent
        	double discountPercent = getDiscountPercent(customerType, subtotal);

        	// 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();
		}
	}
	private static double getDiscountPercent(String customerType, double subtotal)
	{
		double discountPercent = 0.0;
		if (customerType.equalsIgnoreCase("R"))	{
		    if (subtotal < 100)
		        discountPercent = 0;
		    else if (subtotal >= 100 && subtotal < 250)
		        discountPercent = .1;
		    else if (subtotal >= 250 && subtotal < 500)
		        discountPercent = .25;
		    else if (subtotal >= 500)
		    	discountPercent = .3;
		}
		else if (customerType.equalsIgnoreCase("C"))
		{	 discountPercent = .2;		}
		else if (customerType.equalsIgnoreCase("T"))	{
			if (subtotal < 500)
				discountPercent = .4;
			else if (subtotal >= 500)
			    discountPercent = .5;
				}
		return discountPercent;
	}
}

and for my static method code:

public static double getValidCustomerType(Scanner sc, String prompt)
{
	//is this right?
	boolean isValid = false;
	while (isValid ==false);
	{
		System.out.print(prompt);
		//...?	
	if customerType = "x" {
		system.out.print("  Program terminated by the user\n")
		//not sure how to code this?
		else if customerType = "c,r,t"
		{
			return;
		}
		else system.out.print("  *Error* Invalid customer type. Try again."
	
}

Any tips and advice is appreciated. Thanks

[Junky]

if customerType = "x" {

Invalid syntax.
Single equals sign is assignment
Do not compare objects (Strings are objects) with equals signs. Use the equals method instead.
What is customerType?

else if customerType = "c,r,t"

Cannot compare multiple values that way. if customerType equals ... or customerType equals ... or etc. (NOTE this is not correct syntax, research logical operators.)