Your allocation method - malloc + cast - may work for simple classes but overall it's a serious no-no; think you should either be using new/delete, or, if sticking with malloc /free, use placement new and an explicit destructor call respectively.
And the stupidest thing, he uses this malloc in a .cc file, where it would no issue to just use new. Thats the point where I stopped reading. After
auto main() -> int {
...
}
I didn't supposed that anything really meaningful can come...
