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Abnormal behaviour of Integer.MIN_VALUE

 
ajay mittal
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Hi All,

I used the following statements in main function:-

System.out.println(Integer.MIN_VALUE);
System.out.println(-(Integer.MIN_VALUE));

Output:
-2147483648
-2147483648

While obtaining the negative of a negative number i am still getting a negative number. Can anyone let me know the reason for this behaviour.

regards,
Ajay
 
Matthew Brown
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The range that ints can have in Java is -2147483648 to 2147483647. Notice the final digit there.

So, -(-2147483648) is +2147483648, but that's too big to store in an int variable. So you get an overflow, and the value wraps round to the bottom of the range again.
 
ajay mittal
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Thanks Matthew Brown.
 
Darryl Burke
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This is actually mentioned in The Java™ Language Specification
For integer values, negation is the same as subtraction from zero. The Java programming language uses two's-complement representation for integers, and the range of two's-complement values is not symmetric, so negation of the maximum negative int or long results in that same maximum negative number. Overflow occurs in this case, but no exception is thrown.
 
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