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 == 0){
        reg &=(0xF);
    }
    else{
        reg >>= 4; 
    }

    return reg;
}

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

Solving Approach

Depending on position if 0 then extract lower nibble by & masking with 0x0F other wise shifted by 4 to the right if position is 1 referring to upper nibble. 

You can always do one liner return (pos == 0 )? (reg &= 0xF) : (reg >>= 4); if MACRO is used but not recommend it stick to simple :)