17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

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

    return (reg >> (4 * pos)) & 0b1111;
}

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

Main optimization here is to not use an if statement to get the value of pos. Instead, shifting by (4 * pos) takes care of that.