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) 
        reg = reg | (1 << pos);     // set bit
    else if (mode == 0) 
        reg = reg & ~(1 << pos);    // clear bit
    else 
        printf("Invalid mode!\n");
    return reg;
}

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