How do you convert Integer.MIN_VALUE to a positive long?

user_16660290 0
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I'm trying to convert this to a positive long but it is still printing as a negative. When I use other negative integers it works but not Integer.MIN_VALUE

 if(num == Integer.MIN_VALUE){
           long number = -num;
           System.out.println(number);
       }
java
1 Answers

long num = -num; is executed as:

  1. take the int num, and negative it; it's still an int. In other words, it remains Integer.MIN_VALUE - because that's the one negative number amongst all 2^31 of em that doesn't have a positive equivalent, as 0 'takes up space' on the positive side of things.

  2. Then, take the number we now have (still Integer.MIN_VAUE, because -Integer.MIN_VALUE is still Integer.MIN_VALUE), and silently cast it to a long, because that's a widening (safe) conversion, so java will just inject the cast for you.

The fix is to first cast to a long and then negative it:

either:

long number = num;
number = -number;

or in one go:

long number = -((long) num);
user_7686440
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