Split a C++ class declaration

Question

I want to know if I can split a C++ class declaration

Original class

    class P
    {
        private: 
           int id;
           //some really          


        

Answer 1

Yes, it is possible but not in the direct kind of way. Here is what you do:

my_object.h:

struct my_object {
  void fun();

  my_object();
  my_object(my_object const&);
  ~my_object();

  my_object& operator = (my_object);

protected:
  void pfun();

private:
  struct impl;
  std::unique_ptr pimpl;
};

my_object.cpp:

struct my_object::impl {
  void fun() { do stuff...}

  void pfun() { do other stuff... }

  int private_member;
};

my_object::my_object() : pimpl(new impl) {}
my_object::my_object(my_object const& o) : pimpl(new impl(*o.pimpl) {}
my_object::~my_object() {}

my_object& my_object::operator = (my_object o) { swap(pimpl, o.pimpl); return *this; }

void my_object::fun() { pimpl->fun(); }
void my_object::pfun() { pimpl->pfun(); }

As you can see, it's a lot of work and requires the heap. Everything in balance...use when you need to.