17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

#define LOWER_NIBBLE(x)     (x & 0x0F)
#define UPPER_NIBBLE(x)     ((x >> 4) & 0x0F)

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    if (pos == 0) {
        return LOWER_NIBBLE(reg);
    } 
    else{
        return UPPER_NIBBLE(reg);
    } 
}

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