17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
   if(pos == 0){
    reg = reg &0x0f; //make upper nibble 0 
   }
   else{
    reg = reg>>4; //shift input 4bits to right
   }
    return reg;
}

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