Extract the Nibble from an 8-bit Register

#include <stdio.h>
#include <cstdint>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    uint8_t mask = (1 << 4) -1;

    if(pos) {
        reg = (reg >> 4) & mask;
    } else {
        reg &= mask;
    }
    return reg;
}

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