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Java Java Objects Delivering the MVP Applying a Discount Code

How to verify only dollar to be used?

How to verify that only letters and dollar can be used?

4 Answers

Steven Morimoto
PLUS
Steven Morimoto
Courses Plus Student 1,836 Points

In the normalizeDiscountCode verify that only letters or the $ character are used. If any other character is used, throw a IllegalArgumentException with the message Invalid discount code.

I'm assuming that this is the question you are talking about. To check if each character in the String discount code is either a letter or a $ you have to first set up a loop that will loop through each character in discountCode to verify each character. You do that with a for loop.

for(char letter : discountCode.toCharArray())

Within the for loop argument, you then make an if statement explaining that you want only letters and the $ in the discountCode:

 if(! Character.isLetter(letter) && letter != '$')
      {
        throw new IllegalArgumentException("Invalid discount code");
      }
    }
    return discountCode.toUpperCase();

Then of course, don't forget to return the discountCode to upper case before you close with }

I hope this helps you out

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

  private String normalizeDiscountCode(String discountCode)
  {
    for(char letter : discountCode.toCharArray())
    {
      if(! Character.isLetter(letter) && letter != '$')
      {
        throw new IllegalArgumentException("Invalid discount code");
      }
    }
    return discountCode.toUpperCase();
  } 
Pranjal Agnihotri
Pranjal Agnihotri
4,187 Points

Please explain your question properly

Thanks Steven.

Pranjal Agnihotri
Pranjal Agnihotri
4,187 Points
[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 = 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"
    }

  }
}

Hope it helps!!!