17. Extract the Nibble from an 8-bit Register

#include <stdio.h>

int hex2int(char ch)
{
    if (ch >= '0' && ch <= '9')
        return ch - '0';
    if (ch >= 'A' && ch <= 'F')
        return ch - 'A' + 10;
    if (ch >= 'a' && ch <= 'f')
        return ch - 'a' + 10;
    return -1;
}

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    return (reg >> (4*pos)) & 0x0F;
}

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