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Java Java Objects Delivering the MVP Applying a Discount Code

Can some one help me???

I don't understand what I didi wrong...

public class Order {
  private String itemName;
  private int priceInCents;
  private String discountCode;

  public Order(String itemName, int priceInCents) {
    this.itemName = itemName;
    this.priceInCents = priceInCents;

  public String getItemName() {
    return itemName;

  public int getPriceInCents() {
    return priceInCents;

  public String getDiscountCode() {
    return discountCode;

  public void applyDiscountCode(String discountCode) {
    this.discountCode = normalizeDiscountCode(discountCode);
  private String normalizeDiscountCode(String discountCode){

    for (int c = 0;c <= discountCode.length();c++){
      if(!(discountCode.charAt(c) <= 'z') || (discountCode.charAt(c) != '$')){
        throw new IllegalArgumentException ("Please enter something valid.");
    return this.discountCode.toUpperCase();
public class Example {

  public static void main(String[] args) {
    // This is here just for example use cases.

    Order order = new Order(
            "Yoda PEZ Dispenser",

    // These are valid.  They are letters and the $ character only
    order.getDiscountCode(); // ABC

    order.getDiscountCode(); // $ALE

    try {
      // This will throw an exception because it contains numbers
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    try {
      // This will throw as well, because it contains a symbol.
    }catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"


1 Answer

Nicholas Bentzen
Nicholas Bentzen
15,074 Points

There are a few things wrong. First, in your normalizeDiscountCode method, delete "this." in the return statement as that is referring to the global variable; you want to return the one passed in the parameters. Secondly, I see what you were trying to do, but try this:

private String normalizeDiscountCode(String discountCode){
    char[] arr = discountCode.toCharArray();
    for(char c : arr){
      if(!(Character.isLetter(c) || c == '$'))
        throw new IllegalArgumentException("Invalid Discount Code");
    return discountCode.toUpperCase();