Bit Operations using Macros

Code

#include <stdio.h>
#include <stdint.h>

#define set(x) x|=0x84
#define clear(x) x&=~(1<<3)
#define toggle(x) x^=(1<<5)

uint8_t modify_register(uint8_t reg) {
    set(reg);
    clear(reg);
    toggle(reg);
    return reg;
}

int main() {
    uint8_t reg;
    scanf("%hhu", &reg);
    printf("%u", modify_register(reg));
    return 0;
}

Solving Approach