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Start your free trialXuanzheng Lin
2,466 PointsCode is failing
No idea why the code just failed lol.
public class Order {
private String itemName;
private int priceInCents;
private String discountCode;
// cut out class code for brevity - srh
public void applyDiscountCode(String discountCode) {
String want;
try {
want = normalizeDiscountCode(discountCode);
this.discountCode = want;
} catch (IllegalArgumentException iae) {
System.out.print(iae.getMessage());
}
}
private String normalizeDiscountCode (String discountCode) {
for (char letter : discountCode.toCharArray()) {
if (! Character.isLetter(letter) || letter != '$') {
throw new IllegalArgumentException("Invalid discount code.");
}
}
String upper;
upper = discountCode.toUpperCase();
return upper;
}
}
2 Answers
Steve Hunter
57,712 PointsSay we have a character 'a'. That is NOT '$'. So, an OR would throw the error as a != '$'
evaluates to true
. Using an OR we only need one side to be true
for the error to be thrown.
Send in a '1' and this is not a letter so !isLetter('1')
is true
(not-false
) and 1 != '$'
is also true
. So, comparing with &&
will pick this up and throw the error. That's correct.
Same with '$'. It's not a letter so !isLetter('$')
is true
and '$' != '$'
is false. Again, this would evaluate to true
with an OR which would throw the error, when it shouldn't.
Make sense?
Steve.
my head hurts now!
Steve Hunter
57,712 PointsHi there,
You've got some extra code in there that's not needed. You don't need the try/catch block to pass this challenge.
In the normalizeDiscountCode
method, you've correctly used a for:in loop to iterate over the code, converted to a char array. You've not done the comparison correctly, though. I think you need &&
not ||
.
You can also tidy up your returned value by omitting the extra variable. Just return the string with .toUpperCase()
applied directly to it:
private String normalizeDiscountCode(String discountCode){
for (char letter : discountCode.toCharArray()) {
if (!Character.isLetter(letter) && letter != '$') {
throw new IllegalArgumentException("Invalid discount code.");
}
}
return discountCode.toUpperCase();
}
I hope that helps,
Steve.
Xuanzheng Lin
2,466 PointsThanks bro. U r totally right. But can u explain u need && instead of ||?