Write A Function To Determine If A Number Is A Power Of 2

Re:Write A Function To Determine If A Number Is A Power Of 2 by darwinGod on Monday October 18, 2010 @12:03PM (#1803973)

In the final version of x&(x-1)==0, one part was overlooked- negative numbers :)

Take the modulus and do the bitwise check!

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Re:Write A Function To Determine If A Number Is A Power Of 2 by nevinera on Monday October 18, 2010 @12:28PM (#1804090)

Negative numbers cannot be powers of two.

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Re:Write A Function To Determine If A Number Is A Power Of 2 by darwinGod on Monday October 18, 2010 @01:26PM (#1804341)

That's definitely true- but say you want to check for (+/-2)^n, then you would have to deal with negative numbers.

If you go by the Two's complement representation, then for a negative number say (-8), because of sign extention, a check for x&(x-1) would fail.

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