1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode)
{
    if (mode == 1)
    {
        return reg |= (1 << pos);
    }
    else
    {
        return reg &= ~(1 << pos);
    }
}

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