17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // since pos refers to nibble position and not bit position
    // we either shift left 0 (for the lower nibble) or 4 (for the upper nibble).
    unsigned char result = (reg >> (pos == 0 ? 0 : 4)) & 0x0F;
    return result;
}

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