Storing templated objects in a vector (Storing Class, Class in a single vector)

Question

There is a templated class, let it be

template class A { std::vector data; };

The problem I am facing here is,

Answer 1

As previous comments stated - you first need to make sure this is what you need.

With that been said, I had a similar requirement in a project of mine, which I eventually solved with inheritance and PIMPL, as follows:

class A{
private:
    struct Abstract {
        virtual void f() = 0;
    };

    template 
    struct Implementation : public Abstract {
        std::vector data;
        virtual void f() {...}
    };

    std::unique_ptr impl;

public:
    template 
    A(): impl(std::make_unique >()){}

    void f() {impl->f();}
};

This allows you to create a container of objects of type A, and access them via the public interface defined therein (the method f). The underlying type T of each A object is specified on construction. All other implementation details specific to the type T are hidden.

The solution suffers the inherent overhead of virtual functions. I'm not sure how it compares to the std::any approach performance-wise.