C++ template class constructor

Question

I have a class:

template<typename T, typename S>
class filterable_data
{
    /* ... */
};

I create those two instances:

filterable_data<int, char> a;
filterable_data<int, bool> b = a;

My question is, how can I write that constructor properly?

Answer 1

By making it a template too:

template<typename T2, typename S2>
filterable_data(const filterable_data<T2, S2>& other);