1. Set or Clear a Specific Bit in a Register

#include <stdio.h>

unsigned char modifyBit(unsigned char reg, int pos, int mode) {
   // unsigned char res = 0;
    if (mode == 1){
       // res = reg | (1<< pos);
       reg |= (1<<pos);
    }
    else 
    //res = reg & (~(1<<pos));
    reg &= ~(1<<pos);
    return reg;
}

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