programming-examples/c/Bitwise/C Program to Check if a given Integer is Power of 2 using Bitwise Operators.c

/*
 * C Program to Check if a given Integer is Power of 2 using Bitwise Operators
 */
#include <stdio.h>
#define NUM_BITS_INT (8*sizeof(int))

int power_of_2(unsigned int);

int main()
{
    unsigned int num;
    printf("\nEnter Number");
    scanf("%d", &num);
    power_of_2(num);
}

/*
 * Finding the power of 2 using bit wise operators
 */
int power_of_2(unsigned int x)
{
    int i, count = 0, result, shift_num;
    for (i = 0; i <= NUM_BITS_INT; i++)
        {
            shift_num = x >> i;
            result = shift_num & 1;
            if (res == 1)
                count++;
        }
    /*
     *If number of bits set to 1 are odd then the number is power of 2
     *If number of bits set to 0 are even then the number is not power of 2
     */
    if (count % 2 == 1)
        printf("YES");
    else
        printf("NO");
}