17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
   
    if (pos == 0) {
        reg = reg & 0x0F;          // lower nibble
    } else {
        reg = (reg & 0xF0) >> 4;   // upper nibble
    }
    return reg;
}

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