Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    union {
        unsigned char lower : 4;
        unsigned char higher :4;
        unsigned char val;
    }uSplit;
    uSplit.val = reg;
    return (pos == 1 ? uSplit.higher : uSplit.lower );
}

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