normalizeDiscountCode $@ving$ testcase working

Question

I'm trying to run the code and it keeps saying that IllegalArgumentException should be called when the input: $@ving$ is put in. Why and how is $@ving$ even working? Isn't my for loop iterating through all the letters in the String. Then how is the '@' being allowed through? Is the @ symbol being considered as a letter? Thanks to anyone that answers this!

Order.java

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

  private String normalizeDiscountCode (String dCode){
    discountCode = dCode.toUpperCase();
    char[] cArr = discountCode.toCharArray();
    for(char c : cArr) {
     if(!Character.isLetter(c) && discountCode.indexOf('$') == -1) { 
       throw new IllegalArgumentException("Invalid discount code");
     }
    }
    return 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;
    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"
    }

  }
}

Answer 1 · 2018-06-29T09:04:27Z

June 29, 2018 9:04am

There are two problems with your code: 1) in your normalizeDiscountCode method you overwrite the content of the instance variable discountCode

private String normalizeDiscountCode (String dCode){
  discountCode = dCode.toUpperCase(); // <-- this line

Declare your variable in the scope of normalizeDiscountCode method:

private String normalizeDiscountCode (String dCode){
  String discountCode = dCode.toUpperCase(); // <-- this line

2) while looping through characters of discountCode you use indexOf method that is a loop also. So there is an unnecessary loop in your loop. Use simple checking of equality here:

c == '$'

Then you have to think of the truth table, and find out which bitwise operator can be helpful here.

One solution would be using your code:

private static String normalizeDiscountCode2 (String dCode) {
  String discountCode = dCode.toUpperCase();
  char[] cArr = discountCode.toCharArray();
  for(char c : cArr) {
    if(!Character.isLetter(c) ^ c == '$') { 
      throw new IllegalArgumentException("Invalid discount code");
    }
  }
  return discountCode;    
}

My solution:
```Java
private String normalizeDiscountCode(String discountCode) {
  boolean b = true;
  int i = 0;

  while (b && i < discountCode.length()) {
    char c = discountCode.charAt(i);
    b &= Character.isLetter(discountCode.charAt(i)) ^ c == '$';
    i++;
   }

  if(!b) throw new IllegalArgumentException("Invalid discount code");

  return discountCode.toUpperCase();
}

Maybe it's not the most elegant one, but it works, and it doesn't break a for loop.

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Siddesh Gannu

Siddesh Gannu

normalizeDiscountCode $@ving$ testcase working

1 Answer

Gergely Horvath

Gergely Horvath

Gergely Horvath

Gergely Horvath

Gergely Horvath

Gergely Horvath