Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    if(pos == 1)
    {
        reg = ((reg >> 4) & (0x0F));
    }
    else
    {
        reg = (reg & 0x0F);
    }
    return reg;
}

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

Solving Approach

Based on the position of nibble (upper or lower), a bit shif operation is performed. If the upper nibble is preffered, a right shift operation by 4 bits is done and then an and operation with (0x0F) to return the upper nibble value. In case of lower nibble, a simple AND operation with 0x0F will return the lower nibble.