Bit Operations using Macros

Code

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

// Define bitwise macros here
#define SET(REG, POS) (REG |= (1U<<POS))

#define RESET(REG, POS) (REG &= ~(1U << POS))

#define TOG(REG, POS) (REG ^= (1U << POS))

uint8_t modify_register(uint8_t reg) {
    // Apply operations in order
    SET(reg, 2); SET(reg, 7);
    RESET(reg, 3);
    TOG(reg, 5);
    return reg;
}

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

Solving Approach

what about macro functions like 
#define func(var) do{ ... } while(0)
why are they used?