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Thread: Integer type conversions

  1. #1
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    Default Integer type conversions

    Hi everybody, I have a practice task that I can't solve and I need help.

    public class Solution {
        public static void main(String[] args) {
            short number = 9;
            char zero = '0';
            int nine = (char) (zero + number);
            System.out.println(nine);
        }
    }

    Here are the rules:
    1. The program should display text on the screen.
    2. Don't change the screen output command. You can only add cast operators to it.
    3. The main() method must contain a short variable number.
    4. The main() method must contain a char variable zero.
    5. The main() method must contain an int variable nine.
    6. Don't change the initial value of the variables during initialization. You can only add cast operators.
    7. The program should display the number 9.

    If I change the variable nine to char, the assignment is incorrect. Also, I don't get why this code it's not working when zero plus number is equal 57 and the decimal 57 is equal to the character 9.

    If someone knows why this is happening I would also like explaining if possible. I'm not looking just for the answer. Thanks!

  2. #2
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    Default Re: Integer type conversions

    You might be casting it to a char but it's being assigned to an int.

    Regards,
    Jim

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    Default Re: Integer type conversions

    Hey, Jim! Thank you for replying.

    I figure that char + whole number is equal to char, that's why zero and number is equal to 57 because zero(char) + 9(short) is equal to char 9 which is 57 (decimal). If I change int nine = ((short) zero + number);, I still get the same answer 57. Why does this happens If I added short and short.

    Thanks.

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    Default Re: Integer type conversions

    When you assign a char to an int it becomes an int. So int a = (char)'0' is no different than int a = '0'. Same is true with short or byte since when you assign to an int it will simply be assigned with any sign extension requirements. Casting is used when you want to assign something to a type where automatic conversion won't take place (the compiler won't do it for you). Like int a = 3.6 won't work. You need to cast 3.6 to an int to assign it to an int type. So when you add to shorts together and assign to an int, it will do the conversion for you.

    So in the following line:

    int nine = (char)(zero + number) is the same as
    int nine = (zero + number).

    Regards,
    Jim

  5. The Following User Says Thank You to jim829 For This Useful Post:

    martinevtimov (October 19th, 2018)

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