simple any implementation

any

#include <iostream>
#include <memory>
#include <typeinfo>

struct bad_any_cast
{
};

class any
{
  private:
    struct base
    {
      virtual ~base() = default;

      virtual const std::type_info& get_type() = 0;
    };

    template<typename T>
    struct child : public base
    {
      child(T t)
      : mT(t)
      {
      }

      const std::type_info& get_type() override
      {
        return typeid(T);
      }

      T mT;
    };

    std::unique_ptr<base> mpBase;

  public:

    any()
    : mpBase(nullptr)
    {
    }

    template <typename T>
    any(T t)
    : mpBase(std::make_unique<child<T>>(t))
    {
    }

    template <typename T>
    T any_cast()
    {
      if (!mpBase || typeid(T) != get_type())
      {
        throw bad_any_cast{};
      }

      return static_cast<child<T>*> (mpBase.get())->mT;

    }

    const std::type_info& get_type() const
    {
      if (!mpBase)
      {
        return typeid(nullptr);
      }

      return mpBase->get_type();
    }
};

int main()
{
  any a;

  a = 5;

  std::cout << a.any_cast<int>() << std::endl;

  a = "works";

  std::cout << a.any_cast<const char*>() << std::endl;
}