t.lavanya

• Jul 9th, 2006

 

if(x && x-1 ==0) printf(" no. is power of 2");

Suman

• Jul 11th, 2006

 

U can take logarithm base 2, and check the result is in interger form or floating point form, u can check whether it is power of 2 or not.

farha

• Jul 30th, 2006

 

Lavanya,

Can u explain logic. The If condition

Anurag Laddha

• Aug 1st, 2006

 

That's actually logical ANDingThe actual to determine whether a number is a power of 2 or not is --> bit wise AND the number under consideration with its previous number. if the result is zero then the number under consideration is power of 2Code: if (x & (x-1) == 0) number is a power of 2else number is NOT a power of two.

newbie

• Aug 4th, 2006

 

what will happen if x is 0?

Hinstings

 Profile Answers by Hinstings Questions by Hinstings

• Aug 20th, 2006

 

You are right. We should first check whether the given number is larger than 0. If it is larger than 0, we can use (x && (x-1) == 0) to determine whether x is power of 2 or not. If it is 0, then return 0. If x is smaller than 0, what should we do?

Hinstings

 Profile Answers by Hinstings Questions by Hinstings

• Aug 20th, 2006

 

My mistake, actually, what I want to say is "if the given number is like 2^(-2)"? Can we check that.

krisgroup

 Profile Answers by krisgroup 

• Oct 22nd, 2007

 

Hi folks,

I would say try this ...

int result=!((input_no&&input_no-1)&&input_no)

it works a good bit twidling technique,

chaitanya

aravindkumarsingh

 Profile Answers by aravindkumarsingh 

• Jun 4th, 2008

 

# include <stdio.h>
# include <conio.h>
void main()
{
 int x;
 printf("Enter the value of x: ");
 scanf(" %d", &x);
 if((x & (x-1)) ==0)
  printf(" no. is power of 2");
    else
      printf(" no. is not power of 2");

 getch();
}