i'm bit stumped how achieve in c++. have feeling might have architecture.
let's have a garage in montreal , in garage, there different cars.i go vector of pointers base class car here. here problem though, want deep copy garage , open 1 in miami. futhermore, saab cars needs have different copy constructor, same signature. there other exceptions down road. don't know what's in garage beforehand. here code have far.
//base class class car { public: car(int speed); private: int speed; } class garage { public: garage(){}; //copy constructor of garage garage(const garage &tocopy) { for(int i=0;i<tocopy.cars.size();i++) { receivecar(*cars[i]); } } vector<std::shared<car>> cars; template <typename t> t* receivecar() { std::shared_ptr<t> ptr = std::make_shared<t>(); cars.push_back(ptr); return ptr.get(); } t* receivecar(car &tocopy) { std::shared_ptr<t> ptr = std::make_shared<t>(tocopy) cars.push_back(ptr); return ptr.get(); } } class saab : public car { public: saab(int speed) :car(speed) { dowork(); }; } class astonmartin: public car { public: astonmartin(int speed) :car(speed) { doimportantstuff(); }; astonmartin(const astonmartin& tocopy) :car(tocopy.speed) { doimportantstuff(); }; } of course, copy constructor used implicit 1 car. possible call derived class' 1 instead without dynamic casting between ifs/elses every exception rule there is. maybe store each derived classes pointer somehow?
ps:i know should not returning raw pointers, destructors cars private in code, shared_pointers still safe.
in context of inheritance copy constructor should designed called “virtual copy constructor”. these functions called copyself, cloneself or clone.
here elaborated example using copy constructors , virtual copy constructor:
#include <memory> #include <iostream> #include <vector> using std::cout; using std::endl; using std::vector; //base class class car { public: car(int speed): speed(speed) {}; car(const car& c): speed(c.speed) { cout <<"copy constructor car" <<endl; } virtual void display() { cout <<" speed: " <<speed <<endl; } virtual car* clone()const =0; // virtual copy constructor private: int speed; }; typedef std::shared_ptr<car> carp; class garage { private: vector<carp> cars; public: garage() {} //copy constructor of garage garage(const garage &tocopy) { cout <<"copy constructor garage" <<endl; (carp c : tocopy.cars) { carp cp(c->clone()); receivecar(cp); } } void receivecar(carp tocopy) { cars.push_back(tocopy); } void display() { (carp c : cars) c->display(); } }; class saab: public car { public: saab(int speed): car(speed) { cout <<"constructor saab" <<endl; } void display() { cout <<"car: saab"; car::display(); } saab* clone()const { return new saab(*this); } }; class astonmartin: public car { public: astonmartin(int speed): car(speed) { cout <<"constructor astonmartin" <<endl; } astonmartin(const astonmartin& tocopy): car(tocopy) { cout <<"copy constructor astonmartin" <<endl; } void display() { cout <<"car: astonmartin"; car::display(); } astonmartin* clone()const { return new astonmartin(*this); } }; int main() { carp saab =std::make_shared <saab>(100); carp aston =std::make_shared <astonmartin>(200); garage montreal; montreal.receivecar(saab); montreal.receivecar(aston); montreal.display(); garage miami(montreal); // decision offer user copy constructor: miami.display(); } produced output:
constructor saab constructor astonmartin car: saab speed: 100 car: astonmartin speed: 200 copy constructor garage copy constructor car copy constructor car copy constructor astonmartin car: saab speed: 100 car: astonmartin speed: 200 
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