17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    // if(pos == 0) {
    //     reg &= 0x0f;
    // }
    // else {
    //     reg = reg>>4;
    //     reg &= 0x0f;
    // }
    reg >>= (pos * 4);
    reg &= 0x0f;
    return reg;
}

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

instead of conditional execution, we can see that pos*4 gives us the amount we have to right shift by.