Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    unsigned char mask;
    if (pos == 0)
    {
        mask = 0x0F;
        reg &= mask;
    }
    else
    {
        mask = 0xF0;
        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;
}

Solving Approach