checking if a number if a power of 2

Here's my code:

Code:

 ((num & (num - 1)) == 0)

is this true? I tried it and it doesn't work as it's supposed to be. So is there another easier way?

Check if the square root is a whole number.

It should work. What numbers are you using?

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Mats

Originally Posted by whiteflags

Check if the square root is a whole number.

And thus, 25 is a power of 2?

I am trying to use 3

Originally Posted by -EquinoX-

I am trying to use 3

And what result to you expect, and how is that different from what you get? 3 is not a power of 2.

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Mats

oh nvm.. I found my self a stupid little mistake

Originally Posted by brewbuck

And thus, 25 is a power of 2?

Isn't it? 5 squared...

Power of two means two raised to a power, not a number raised to the second power. It's 2^x not x^2.

edit: The reason that first equation works is that any power of a number will be 1000 in that number system. 10, 100, 1000 are all powers of ten in the base-ten system. In base-two, they are all powers of two. Subtract one, and there will be a one in place of all the zeroes. 100 - 1 = 011. 100 & 011 = 0.

Originally Posted by whiteflags

Isn't it? 5 squared...

... Making it a power of 5.

Can you slap your forehead for me? I can't reach you

Originally Posted by iMalc

... Making it a power of 5.

Which reminds me suddenly:

"Power of 3
Make us free,
Power of 3
Make us free..."

(c) Charmed

iMalc, do you need some power of 3 to reach him remotely?