17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

#define LOWER   0
#define HIGHER  1
#define LOWER_NIBBLE    4

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    if (pos == HIGHER)
        return reg >> LOWER_NIBBLE;
    else if (pos == LOWER)
        return reg & 0x0F;
    else
        return 0;
}

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