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Start your free trialSorin Ocneanu
2,767 PointsWhat did I do wrong?
I don't really understand what I did wrong here Can someone please explain? It says: "Bummer: java.lang.IllegalArgumentException: Invalid discount code (Look around Order.java line 31)"
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) {
for ( char letter : discountCode.toCharArray() ) {
if ( !(Character.isLetter(letter)) || !(letter == '$') ) {
throw new IllegalArgumentException("Invalid discount code");
}
}
discountCode = discountCode.toUpperCase();
return discountCode;
}
}
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(); // $ALE
try {
// This will throw an exception because it contains numbers
order.applyDiscountCode("ABC123");
} catch (IllegalArgumentException iae) {
System.out.println(iae.getMessage()); // Prints "Invalid discount code"
}
try {
// This will throw as well, because it contains a symbol.
order.applyDiscountCode("w@w");
}catch (IllegalArgumentException iae) {
System.out.println(iae.getMessage()); // Prints "Invalid discount code"
}
}
}
1 Answer
Simon Coates
8,377 PointsI think you've incorrectly applied demorgan's law. It seems to accept
private String normalizeDiscountCode(String discountCode) {
for (char letter : discountCode.toCharArray() ) {
if ( !Character.isLetter(letter) && letter != '$' ) {
throw new IllegalArgumentException("Invalid discount code.");
}
}
return discountCode.toUpperCase();
}
A character is valid if it's a letter OR it's a $. To invert things, it becomes if not a letter AND not a $. (In honesty, a lot of people trip over this one. There are 14 pages of community questions for that challenge. I've written that code at least 10 times and I still have to think about the conditions)
Sorin Ocneanu
2,767 PointsSorin Ocneanu
2,767 PointsThank you!