17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    if (pos == 0) {
        unsigned char mask = 15;
        reg = reg & mask;
    } else if (pos == 1) {
        unsigned char mask = 240;
        reg = (reg & mask) >> 4;
    } return reg;
}

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