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 i;
    unsigned char result=0;
    if (pos == 0){
        for (i=0;i<4;i++){
            if ((reg & (1<<i)) ==0) result &= ~(1<<i);
            else result |= (1<<i);
        }
    }
    else if (pos ==1){
        int n=0;
        for(i=4;i<8;i++){
             if ((reg & (1<<i))==0) result &= ~(1<<n);
             else result |= (1<<n);
             n+=1;
        }
    }
    return result;
}

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