Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos)
{
    // Write your code here
    unsigned char retval;
    if(pos == 0) // lower nibble
    {
        retval = reg & 0x0F;
    }
    else
    {
        retval = (reg & 0xF0) >> 4;
    }
    return retval;
}

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

Solving Approach