1. Set or Clear a Specific Bit in a Register

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

#define SET(reg, pos) reg | (1U << pos)
#define CLEAR(reg, pos) reg & ~(1U << pos)

uint8_t modifyBit(uint8_t reg, int pos, int mode) 
{
    if(mode)
    {
        return SET(reg, pos);   
    }
    else
    {
        return CLEAR(reg, pos);
    }
}

int main() 
{
    uint8_t reg;
    int pos, mode;
    scanf("%hhu %d %d", &reg, &pos, &mode);
    printf("%d", modifyBit(reg, pos, mode));
    return 0;
}