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Java Java Objects Delivering the MVP Applying a Discount Code

Albert Kirchmeyr
Albert Kirchmeyr
11,410 Points

Part 1 no longer passing

After passing task 1 I check for letters and the $ sign....after my check I get part 1 is no longer passing....

WHY?

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) { try { this.discountCode = normalizeDiscountCode(discountCode); } catch (IllegalArgumentException iae) { System.out.println(iae.getMessage()); } }

private String normalizeDiscountCode(String discountCode) { discountCode = discountCode.toUpperCase(); for (char check : discountCode.toCharArray()) { if (! Character.isLetter(check) || check != '$') { throw new IllegalArgumentException("Invalid discount code"); } }
return discountCode; } }

Order.java
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) {
    try {
    this.discountCode = normalizeDiscountCode(discountCode);
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());
    }
  }

  private String normalizeDiscountCode(String discountCode) {
    discountCode = discountCode.toUpperCase();
    for (char check : discountCode.toCharArray()) {
      if (! Character.isLetter(check) || check != '$') {
      throw new IllegalArgumentException("Invalid discount code");
      }
    }        
    return discountCode;
  }
}
Example.java
public class Example {

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

    Order order = new Order(
            "Yoda PEZ Dispenser",
            600);

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

    order.applyDiscountCode("$ale");
    order.getDiscountCode(); // $ALE


    try {
      // This will throw an exception because it contains numbers
      order.applyDiscountCode("ABC123");
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    }
    try {
      // This will throw as well, because it contains a symbol.
      order.applyDiscountCode("w@w");
    }catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    }

  }
}

1 Answer

Yanuar Prakoso
Yanuar Prakoso
15,196 Points

Hi Albert The problem is in your if statement. This is your if statement:

if (! Character.isLetter(check) || check != '$') //this is wrong

It should be:

if ( !( Character.isLetter(check) || check == '$'))

The request is to verify whether the Discount code contains only letters or "$" character. If Not then throw exception. Thus we may say IF there is any character is NOT(letters OR "$") THEN Throw something. Thus if we write it in logical expression it will be like: if (NOT(Character.isLetter(check) OR check =="$"))

in other word: if (!(Character.isLetter(check) || check == "$"))

If you still wanted to includes the negation operator (which is the ! character) attached to each statement you may do so but please the OR operator (the ||) into AND operator ('&&'). Like this:

if (!Character.isLetter(check) && check != '$') 

for the reason of this please search through Google about logical expressions if you are still curious.

I hope this can help you pass the challenge.

Albert Kirchmeyr
Albert Kirchmeyr
11,410 Points

Thank you! It's so easy to oversee this things!

Thank you for your great explanation!