Bitwise filter function and ODD Number

Based on whether num is odd or even it will give 0 and 1

But sir that problem finally is delivering odd values.

5 & 1 will give 0
4 & 1 will give 1

Let say for example:
23 & 1 = 1 + 0(last digits of 8 bits binary) = 0 → This will return 0 and this is getting filtered in the final filtered array.
Based on some explanation here.