is_power_of_two

popcount.c

#include <stdbool.h>
#include <stdio.h>

bool is_power_of_two(size_t);
int my_pop_count(size_t);

int main()
{
	size_t n = 8;

	if(is_power_of_two(n)) {
		fprintf(stdout, "%zu is a power of 2\n", n);
	} else {
		fprintf(stdout, "%zu is not a power of 2\n", n);
	}
   
	return 0;
}

bool is_power_of_two(size_t x)
{
	return my_pop_count(x) > 1 ? false : true;
}

/*
 * return the Hamming Weight
 * 
 * IS_POWER_OF_2(x) my_pop_count(x) > 1 ? false : true
 */
int my_pop_count(size_t x)
{
	unsigned setBits = 0;
	do {
		int rem = x % 2;
		if(rem == 1) {
			setBits++;
		}
		x = x / 2;
	} while(x != 0);
	
	return setBits;
}