#include <stdio.h>

template<typename T>
class smart_ptr
{
public:
	T* operator->()	{if(ptr) return ptr; throw -1;}

	T& operator*() {if(ptr) return *ptr; return NULL;}
	
	smart_ptr()	{ptr = NULL;}
	
	smart_ptr(T* p):ptr(p) {}
	
	~smart_ptr() {if (ptr) delete(ptr); ptr = NULL;}		

	smart_ptr& operator=(T* p) {if(ptr) delete(ptr); ptr = p; return *this;}

	bool operator==(const T& p1) {return (p1.ptr == ptr);}

	bool operator==(const int i) {return (i == (int)ptr);}

protected:
	T* ptr;
};

class myclass
{
public:
	int a;
	int b;
	
	myclass() {printf("\n new myclass object created.");}
	~myclass() {printf("\n myclass object deleted.");}
};

//test1: one smart_ptr assgined twice
void test1()
{
	smart_ptr<myclass> pObj1 = new myclass;
	pObj1->a = 100;
	
	pObj1 = new myclass;
}

//test2: assigning one smart_ptr to another
void test2()
{
	smart_ptr<myclass> pObj1;
	pObj1 = new myclass;
	
	smart_ptr<myclass> pObj2;
	pObj2 = pObj1;
}

//test3: using uninitialized pointer
void test3()
{
	try
	{
		smart_ptr<myclass> pObj1;
		pObj1->a = 100;
	}
	catch(int e)
	{
		printf("\n invalid pointer reference");
	}
}

int main()
{
	printf("\ntest1");
	test1();
	
	//printf("\ntest2");
	//test2();	
	
	printf("\ntest3");
	test3();

	printf("\nend of program\n");

	return 0;
}