Java (for beginners) problem

BolBill

Getting the following error
"Exception in thread "main" java lang.NullPointerException at TicketPriceWithDiscount.main(TicketPriceWithDiscount.java:17)

after the second question re the coupon.
Heres the code:


import java.util.Scanner;

class TicketPriceWithDiscount {
public static void main(String args[]) {
Scanner myScanner = new Scanner(System.in);
int age;
double price = 0.00 ;
char reply;



System.out.print("What is your age?: ");
age = myScanner.nextInt();


System.out.print("Have you a coupon? (Y/N) ");
reply = myScanner.findInLine(".").charAt(0);


if (age >= 12 && age < 65) {
price = 9.25;
}
if (age < 12 || age >= 65) {
price = 5.25;
}
if (reply == 'Y' || reply == 'y') {
price -= 2.00;
}
if (reply == 'Y' || reply =='y'
|| reply =='N' || reply =='n') {
System.out.println("huh?");
}

System.out.print("Please Pay $");
System.out.print(price);
System.out.print(". ");
System.out.println("Enjoy the show!");

}
}


Anybody help ?

Draupnir

Your line doesnt contain '.' and therefore, you cannot do charAt(0) on nothing. i.e. Null pointer exception.

BolBill

Draupnir wrote: »

Your line doesnt contain '.' and therefore, you cannot do charAt(0) on nothing. i.e. Null pointer exception.

Ok thanks. So what do I do ?

Epic Tissue

System.out.println("Have you got a coupon?: ");
reply = scanner.nextLine();

Does that work?

BolBill

No, it looks for a char

Genghiz Cohen

Strings are enclosed in "S"
Chars are 'C'.
I think....
It's been a while but I think this happened to me....

Epic Tissue

BolBill wrote: »

No, it looks for a char

you can get a char from a string with charAt like you did.

so..

System.out.print("Have you got a coupon?: Y/N");
reply = myScanner.nextLine().charAt(0);

edit:

seems to only work when you ask for Y/N before you ask for age. I don't know why this is... can anyone explain that?

Donald-Duck

Been awhile since I used scanner but I assume its because nextInt hasn't terminated the line, so the "nextLine" is more than likely an empty string.

You can just use ".next()"(Doesn't care about newlines ) to get the next string, and .charAt(0) to get the Y/N part of it

eoinbn

Your code isn't very robost. For example you will get an error if you put in a letter instead of a number for the age question.

static Scanner myScanner = new Scanner(System.in);

public static boolean question() {
while (true) {
String answer;
System.out.print("Have you a coupon? (Y/N) ");
answer = myScanner.next();
if (answer.equalsIgnoreCase("Y"))
return true;
else if (answer.equalsIgnoreCase("N"))
return false;
}

}

I would use something like that. It just loops until it gets a Y or N(and ignores caps).

BolBill

I used myScanner.next().charAt(0); and it works.

Thanks for all your help folks, much appreciated.