Bit Operations using Macros

Code

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

#define BIT(n) (1u << (n))
#define SET_BIT(reg, n) ((reg) |= BIT(n))
#define CLEAR_BIT(reg, n) ((reg) &= ~BIT(n))
#define TOGGLE_BIT(reg, n) ((reg) ^= BIT(n))

// Now, whenever BIT(n) is encountered, the compiler replaces it with (1u << (n))
// So, SET_BIT(reg, n) is replaced with reg |= bit(n) => reg |= (1u << n)

uint8_t modify_register(uint8_t reg){

    SET_BIT(reg, 2);
    SET_BIT(reg, 7);
    CLEAR_BIT(reg, 3);
    TOGGLE_BIT(reg, 5);

    /*
    This entire block is replaced with:

    reg |= 0b10000100;
    reg &= ~0b00001000;
    reg ^= 0b00100000;
    */

    return reg;
}

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

Solving Approach