Rightmost Bit of a Number

You can determine the rightmost bit (the least significant bit) in the binary representation of a positive integer using modulo division by two.

Now that you have the rightmost bit, all you need to do is find the rest of the bits (shown above as _ _ _ _ ).

Think about erasing the rightmost 0 or 1 bit in the above. (The same as shifting the bits right by one position.) You are left with _ _ _ _ . Those bits represent [N div 2], because shifting right is equivalent to integer dividing by two.