stock_visitor.cpp

//Write CPP code here 

#include <iostream> 
using namespace std; 

class Stock 
{ 
public: 
	virtual void accept(class Visitor *) = 0; 
	
}; 

class Apple : public Stock 
{ 
public: 
	/*virtual*/ void accept(Visitor *); 
	void buy() 
	{ 
		cout << "Apple::buy\n"; 
	} 
	void sell() 
	{ 
		cout << "Apple::sell\n"; 
	} 
	
}; 
class Google : public Stock 
{ 
public: 
	/*virtual*/ void accept(Visitor *); 
	void buy() 
	{ 
		cout << "Google::buy\n"; 
	} 

	void sell() 
	{ 
		cout << "Google::sell\n"; 
	} 
}; 

class Visitor 
{ 
public: 
	virtual void visit(Apple *) = 0; 
	virtual void visit(Google *) = 0; 
	//private: 
	static int m_num_apple, m_num_google; 
	void total_stocks() 
	{ 
		cout << "m_num_apple " << m_num_apple 
			<< ", m_num_google " << m_num_google << '\n'; 
	} 
}; 
int Visitor::m_num_apple = 0; 
int Visitor::m_num_google = 0; 
class BuyVisitor : public Visitor 
{ 
public: 
	BuyVisitor() 
	{ 
		m_num_apple = m_num_google = 0; 
	} 
	/*virtual*/ void visit(Apple *r) 
	{ 
		++m_num_apple; 
		r->buy(); 
		cout << "m_num_apple " << m_num_apple << endl; 
	} 
	/*virtual*/ void visit(Google *b) 
	{ 
		++m_num_google; 
		b->buy(); 
		cout << " m_num_google " << m_num_google << '\n'; 
	} 
}; 

class SellVisitor : public Visitor 
{ 
public: 
	/*virtual*/ void visit(Apple *a) 
	{ 
		
		--m_num_apple; 
		a->sell(); 
		cout << "m_num_apple " << m_num_apple << endl; 
	} 
	/*virtual*/ void visit(Google *g) 
	{ 
		--m_num_google; 
		g->sell(); 
		cout << "m_num_google " << m_num_google << endl; 
	} 
}; 

void Apple::accept(Visitor *v) 
{ 
	v->visit(this); 
} 

void Google::accept(Visitor *v) 
{ 
	v->visit(this); 
} 

int main() 
{ 
	Stock *set[] = { new Apple, new Google, new Google, 
					new Apple, new Apple, 0 }; 

	BuyVisitor buy_operation; 
	SellVisitor sell_operation; 
	for (int i = 0; set[i]; i++) 
	{ 
		set[i]->accept(&buy_operation); 
	} 
	buy_operation.total_stocks(); 

	for (int i = 0; set[i]; i++) 
	{ 

		set[i]->accept(&sell_operation); 
	} 
	sell_operation.total_stocks(); 
}