智能指针：shared_ptr简单实现

#include <iostream>

using namespace std;

template <typename T>
class Shared_ptr {
public:
	Shared_ptr(T* p) : count(new int(1)), _ptr(p) {}
	Shared_ptr(Shared_ptr<T>& other) : count(&(++*other.count)), _ptr(other._ptr) {}
	T* operator->() { return _ptr; }
	T& operator*() { return *_ptr; }

	Shared_ptr<T>& operator=(Shared_ptr<T>& other)
	{
		++*other.count;
		if (this->_ptr && 0 == --*this->count)
		{
			delete count;
			delete _ptr;
		}
		this->_ptr = other._ptr;
		this->count = other.count;
		return *this;
	}

	~Shared_ptr()
	{
		if (--*count == 0)
		{
			delete count;
			delete _ptr;
		}
	}
	int getRef() { return *count; }
private:
	int* count;
	T* _ptr;
};


int main(){
	
	Shared_ptr<string> pstr(new string("abc"));
	Shared_ptr<string> pstr2(pstr);

	Shared_ptr<string> pstr3(new string("hao"));
	pstr3 = pstr2;

	cout << "share_ptr 引用个数为:" << pstr3.getRef() << endl;

	return 0;
}