Question

How to define macros to get bit, set bit, clear bit and flip bit in C

Answer 1

#include <stdio.h>

#define GetBit(num, bit) ((num & (1 << bit)) != 0) 
#define SetBit(num, bit) (num |= (1 << bit))
#define FlipBit(num, bit) (num ^= (1 << bit))
#define ClearBit(num, bit) (num &= ~(1 << bit))

void print_bits(unsigned int num, unsigned int size) {
    for (int i = 1 << (size - 1); i > 0; i = i / 2) {
        (num & i) ? printf("1") : printf("0");
    }
}

int main() {
    unsigned int num = 0;
    
    SetBit(num, 3);
    print_bits(num, 8);
    
    printf("\n");
    (GetBit(num, 5)) ? printf("1") : printf("0");
    
    printf("\n");
    (GetBit(num, 3)) ? printf("1") : printf("0");
    
    FlipBit(num, 5);
    printf("\n");
    print_bits(num, 8);
    
    ClearBit(num, 3);
    printf("\n");
    print_bits(num, 8);
    
    return 0;
}
 
 
 
 
/*
run:
 
00001000
0
1
00101000
00100000
 
*/

 

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