You cannot do anything meaningful with a container of arbitrary types, it's just bad design. If you want to apply the same operation on all of them, then they

You cannot do anything meaningful with a container of arbitrary types, it's just bad design. If you want to apply the same operation on all of them, then they share some API commonality -- therefore you can use polymorphism or type erasure. If they don't, you still need to know what types they are -- therefore you can use `std::variant`. If they really are unrelated, why are you storing them together in the same container? Even then, it's trivial in C++: `std::vector<std::any>`.