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;
    if(pos==1){
        for(i=0;i<4;i++){
            reg&=~(1<<i);
           
        }
        reg=reg>>i;
        
    }
    if(pos==0){
        for(i=8;i>=4;i--){
            reg&=~(1<<i);
        }
    }
        return reg;
    
}

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