#include <iostream>
#include <vector>

class A{
    public:
    int value;
    A() : value(1){}
    A(int x) : value(x){}
};


template<class C>
class B{
    public:
    std::vector<C> v;
};


int main() {
    A a{100};
    B<A> b{};

    b.v.push_back(a);

    std::cout << b.v[0].value << std::endl;



    return 0;
}