Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Objects Delivering the MVP Applying a Discount Code

Tree House
Tree House
19,702 Points

Applying disount error

What do i wrong?

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;
  }
 private String normalizeDiscountCode(String discountCode) {
   for (char letter: discountCode.toCharArray()){
   if ( ! Character.isLetter(discountCode) && !discountCode.contains('$'))
    throw new IllegalArgumentException("invalid discount code"); 
   }
    return this.discountCode = discountCode.toUpperCase();
  }
  public void applyDiscountCode(String discountCode) {
    this.discountCode = normalizeDiscountCode(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

Brendan Whiting
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Brendan Whiting
Front End Web Development Techdegree Graduate 84,738 Points

I'm seeing these errors in the Preview window:

./Order.java:24: error: no suitable method found for isLetter(String)
   if ( ! Character.isLetter(discountCode) && !discountCode.contains('$'))
                   ^
    method Character.isLetter(char) is not applicable
      (argument mismatch; String cannot be converted to char)
    method Character.isLetter(int) is not applicable
      (argument mismatch; String cannot be converted to int)
./Order.java:24: error: incompatible types: char cannot be converted to CharSequence
   if ( ! Character.isLetter(discountCode) && !discountCode.contains('$'))
                                                                     ^
Note: JavaTester.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output
2 errors

The first error is that you're passing in discountCode, the entire string, into isLetter rather then letter, the single char variable you made as we're iterating through the string. The second error is that you're passing in a single char into the contains method instead of a sequences of chars that it expects. I suggest you just simply test to see if that same letter variable equals '$' rather than using the contains method.

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