Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    int i,j,ch;
    unsigned char res=0;
    if(pos==0)
    {
        ch=1;
        for(i=0;i<4;i++,ch=ch*2)
        {
            res=res+(reg>>i&1)*ch;
        }
    }
    else
    {
        ch=1;
        for(i=4;i<8;i++,ch=ch*2)
        {
            res=res+(reg>>i&1)*ch;
        }

    }
    return res;
}

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

Solving Approach