Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    if(pos == 0){
        reg = reg << 4; //lower bits
        unsigned char lo_bits = reg >> 4;
        return lo_bits;
    }

    if(pos == 1){
        reg = reg >> 4; //upper bits
        return reg;
    }
}

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

Solving Approach