Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    unsigned char mask = 0b1111;
    if (pos) {
        reg = (reg>>4) & mask;
    } else {
        reg = reg & mask;
    }
    return reg;
}

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