17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

#define MASK_NIBBLE(reg, pos)  (reg>>(pos*4)) & 0x0F;

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here

    return reg & MASK_NIBBLE(reg, pos);
}

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