17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    int num = reg;
    int i=0;
    int j=0;
    if(pos) {
        j=3;
    } else {
        i=4;
        j=7;
    }
    for(;i<=j;i++)
    {
        if(num &(1<<i)) {
            num = num ^ (1<<i);
        }
    }
    if (pos) {
        num = num >> 4;
    }
    return num;
}

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