1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
    if (reg < 0 || reg > 255 || pos < 0 || pos > 7 || (mode != 0 && mode != 1))
    {
        printf("Invalid input\n");
        return 1;
    }

    if(mode == 1)
    {
        reg |= (1<<pos);
        return reg;
    }
    else if(mode == 0)
    {
        reg &= ~(1<<pos);
        return reg;
    }
    else
    {
        printf("invalid position");
    }
    return 0;
}

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