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 output;
   if(mode==1) {
    output=(reg |= (1 << pos));   // Set bit n
    }
   if(mode==0){
    output=(reg &= ~(1 << pos));

   }
   return output;
}

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