1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

#include <stdint.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {

    if(mode==0)

        reg &= ~(1<<pos);

    else if (mode==1)

        reg |= (1<<pos);

    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;

}