Please help! Been stuck all day

Question

I have to say I kinda give up on this one. Can someone please give the logic behind the answer to this and correct my errors?

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) {
    this.discountCode = normalizeDiscountCode(discountCode);
  }
  private String normalizeDiscountCode(String discountCode){

    if(discountCode.indexOf(discountCode)!=-1){
      throw new IllegalArgumentException("Invalid discount code.");
    }
    return discountCode.toUpperCase(); 
  }
}

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"
    }

  }
}

Answer 1 · 2017-07-14T09:46:35Z

July 14, 2017 9:46am

Hi there,

You have to check every char in that String. So you would have to loop over every char to check.

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

Just for explanation if

c is a letter it returns true -> thanks to ! it will be false and won't throw an Exception
c is not a letter -> check if c is a $
- c is a $ it returns true -> thanks to ! it will be false and won't throw an Exception
- c is not $ it returns false -> thanks to ! it will be true and will throw an Exception

I hope I expressed it easy to understand.

Have fun

Answer 2 · 2017-08-16T20:20:24Z

August 16, 2017 8:20pm

Thank you for this! I was struggling mightily on this. I actually started using the toCharArray approach but figured I was just overcomplicating it. Apparently I was on the right track, I should have just stuck with it lol.

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Amir Tamim

Amir Tamim

Please help! Been stuck all day

Amir Tamim

Amir Tamim

2 Answers

Felix Sonnenholzer

Felix Sonnenholzer

Christopher Ekeren

Christopher Ekeren