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 |= (1 << pos);
}

if(mode == 0){
    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;
}