check if a number is of 2's power

Sunday, 17 November 2013 | Unknown at 01:07 |

It is generally asked in interviews to check if a number can be converted into 2's power or not.

For e.g 

8= 2^3

16=2^4

and so on...

Now if we solve this program without bit manipulation operators,

It will be difficult to solve it.

Hint:

IF a number is of 2's power, then its binary representation will have only one 1.

e.g 16= 10000

      8 = 1000

and you may check for any number.

Now the problem is, how to implement this logic.

let say our number is 16,

then 

 binary of 16= 10000

and 

binary of 15= 01111

16 & 15 = 00000

This result is only possible when number is of 2's power.

So generalized concept is

 x = number & (number-1)

if(x==0)

{

printf("number is of 2's power");

}

else

{

 printf("Tata bye bye.");

}

Cheers !!!!