Question

How to determining if an integer is a power of 2 in C

Answer 1

#include <stdio.h>
#include <stdbool.h>
 
void print_bits(unsigned int n) { 
    int bit;
    for (int i = 7; i >= 0; i--) {
        bit = n >> i;
        if (bit & 1)
            printf("1");
        else
            printf("0");
    }
    printf("\n");
}
 
int main() {
    unsigned int n = 16;

    print_bits(n);
    print_bits(n - 1);
    print_bits(n & (n - 1));
      
    bool b = (n & (n - 1)) == 0;
  
    printf("%i", b);
}
 


/*
run:
 
00010000
00001111
00000000
1
 
*/

 

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