Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    if(pos == 0)
    {
        // return (reg & ((1 << 4)-1));
        return (reg & (0x0F));
    }
    else if(pos == 1)
    {
        return (reg & ~(0x0F))>>4;
    }
}

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

Solving Approach