#include<iostream>
#include<vector>
#include<string>
#include<math.h>
using namespace std;
class eventhandler
{
public:
	virtual void execute()=0; 
};
class handlerlist
{
public:
	virtual void add(eventhandler* h)=0;
	virtual void dispatch()=0;
};
class events 
{
public:
	virtual string getname()=0;
	//static const string name;
	handlerlist* list;
	
};


class event_add : public events
{
public:
	event_add(){};
	event_add(handlerlist* l)
	{
		list=l;
	}
	string getname()
	{
		return "+";
	}

	//static const string name;
};
class event_mul : public events
{
public:
	event_mul(){};
	event_mul(handlerlist* l)
	{
		list=l;
	}
	string getname()
	{
		return "*";
	}

	//static const string name;
};
class event_subtract : public events
{
public:
	event_subtract(){}
	event_subtract(handlerlist* l)
	{
		list=l;
	}
	string getname()
	{
		return "-";
	}
	//static const string name;
};


class eventhandler_add_list : public handlerlist{

protected :
	vector<eventhandler*> handlers;
public :
	void add(eventhandler* c) 
	{ 
		handlers.push_back(c); 
	}
	void dispatch() 
	{
		vector<eventhandler*>::iterator it;
		it = handlers.begin();
		while(it != handlers.end())  
		(*it++)->execute();
	}
};
class add_handler1 : public eventhandler
{
	public:
		void execute ()
		{
			int x,y;
			cout<<"enter 2 integers to be added seperated by spaces: ";
			cin>>x;
			cin>>y;
			cout<<x<<"+"<<y<<"="<<x+y<<endl;
		}
};
class add_handler2 : public eventhandler
{
public:
	void execute ()
	{
		int x,y,z;
		cout<<"enter 3 integers to be added seperated by spaces: ";
		cin>>x;
		cin>>y;
		cin>>z;
		cout<<x<<"+"<<y<<"+"<<z<<"="<<x+y+z<<endl;
	}
};
class add_handler3 : public eventhandler
{
	public:
		void execute ()
		{
			int x;
			cout<<"enter one integers   ";
			cin>>x;
			
			cout<<x<<"*"<<x<<"="<<x*x<<endl;
		}
};


class eventhandler_mul_list : public handlerlist
{
protected :
	vector<eventhandler*> handlers;
public :
	void mul(eventhandler* c) 
	{ 
		handlers.push_back(c); 
	}
	void dispatch() 
	{
		vector<eventhandler*>::iterator it;
		it = handlers.begin();
		while(it != handlers.end())  
		(*it++)->execute();
	}
};
class mul_handler1 : public eventhandler
{
	public:
		void execute ()
		{
			int x;
			cout<<"enter one integers   ";
			cin>>x;
			
			cout<<x<<"*"<<x<<"="<<x*x<<endl;
		}
};

class eventhandler_subtract_list : public handlerlist

{
      protected :
	vector<eventhandler*> handlers;
public :
	void add(eventhandler* c) 
	{ 
		handlers.push_back(c); 
	}
	void dispatch() 
	{
		vector<eventhandler*>::iterator it;
		it = handlers.begin();
		while(it != handlers.end())  
		(*it++)->execute();
	}
};
class subtract_handler1 : public eventhandler
{
	public:
		void execute ()
		{
			int x,y;
			cout<<"enter 2 integers to be subtracted : ";
			cin>>x;
			cin>>y;
			cout<<x<<"-"<<y<<"="<<x-y<<endl;
		}
};
class subtract_handler2 : public eventhandler
{
public:
	void execute ()
	{
		float x,y;
		cout<<"enter 2 floating point numbers to be subtracted: ";
		cin>>x;
		cin>>y;
		cout<<x<<"-"<<y<<"="<<x-y<<endl;
	}
};
 /*const string event_add::name = "+";
 const string event_subtract::name = "-";*/

int main()
{
	eventhandler_add_list a;
	eventhandler_subtract_list s;
    eventhandler_mul_list m;
	mul_handler1 m1;
    add_handler1 a1;
	add_handler2 a2;
	add_handler3 a3;
	subtract_handler1 s1;
	subtract_handler2 s2;

	event_add add(&a);
	event_subtract subtract(&s);event_mul mul(&m);
	vector<events*> e;
	e.push_back(&add);
	e.push_back(&subtract);
	e.push_back(&mul);
    add.list->add(&a1);
	add.list->add(&a2);
	add.list->add(&a3);
	subtract.list->add(&s1);
	subtract.list->add(&s2);
	mul.list->add(&m1);
/*	eventhandler_pow_list m;
	mul_handler1 m1;
	event_mul pow(&m);
	e.push_back(&pow);
	pow.list->pow(&m1);
	*/
	while(1)
	{
		string s;
		cout<<"enter the event name (+ or - or *) or q to quit:";
		cin>>s;
		if(s=="q")
			exit(0);
		for(int i=0; i<e.size() ; i++)
		{
			if(s==e[i]->getname())
				e[i]->list->dispatch();
		}
		
	}
		

}