C++智能指针

这玩意儿好像不是那么难，但是感觉线程不是那么安全，多个线程在拿某一个时可能加的数不够，只能加锁处理了，参考了一些别人的代码，但是大多数都是自己写的，如果有什么严重的错误可以联系我，正好我学习一下，QQ2971415531。

#include<iostream>
using namespace std;
template<typename T>
class sharedptr {
private:
	T* data_ptr;
	int* count;
public:
	friend class sharedptr;
		//默认
	sharedptr():data_ptr(nullptr), count(new int) {};
	sharedptr(T* data):data_ptr(data),count(new int) {
		*count = 1;
	}
	//拷贝
	sharedptr(const sharedptr& other) {
		data_ptr = other.data_ptr;
		count = other.count;
		++(*count);
	}
	//赋值
	sharedptr& operator=(const sharedptr& other) {
		data_ptr = other.data_ptr;
		count = other.count;
		++(*count);
		return *this;
	}
	//移动
	sharedptr(sharedptr&& other) {
		data_ptr = other.data_ptr;
		count = other.count;
		other.data_ptr = nullptr;
		other.count = nullptr;
	}
	int get_num() {
		if (count) {
			return *count;
		}
		else {
			cout << "这玩意儿已经没了" << endl;
			return -1;
		}
	}
	T& operator*() {
		return *data_ptr;
	}
	T* operator->(){
		return data_ptr;
	}
	~sharedptr(){
		if (count && data_ptr) {
			(*count)--;
			if (*count == 0 && data_ptr) {
				cout << "西沟了" << endl;
				delete data_ptr;
				delete count;
			}
		}
		//(*count)--;
		//if (*count == 0 && data_ptr) {
		//	cout << "西沟了" << endl;
		//	delete data_ptr;
		//	delete count;
		//}
	}
};
int main() {
	int* a = new int(5);
	sharedptr<int> ptr(a);
	sharedptr<int> ptr2(move(ptr));
	cout << ptr.get_num() << endl; 
}

顺便把迭代器也写了得了

template<typename T>
class Node {
public:
	Node(){};
	Node(T n) :data(n),next(nullptr) {};
	T data;
	Node* next;
};

template<typename T>
class List {
public:
	List():length(0),node(nullptr) {};
	T length;
	Node<T>* node;
	class Iterator {
	public:
		Node<T>* current;
		Iterator(Node<T>* start) : current(start) {}
		Iterator& operator++() {
			current = current->next;
			return *this;
		}
		Iterator& operator++(T) {
			current = current->next;
			return *this;
		}
		//bool operator!=(Iterator& it) {
		//	return current != it.current;
		//}
		bool operator!=(const Iterator& it) {
			return current != it.current;
		}
		T operator*() {
			return current->data;
		}
	};
	Iterator begin() {
		return Iterator(node);
	}
	Iterator end() {
		return Iterator(nullptr);
	}
	void push(T input) {
		Node<T>* temp = new Node<T>(input);
		if (node == nullptr) {
			node = temp;
		}
		else {
			Node<T>* lll = node;
			while(lll->next)lll = lll->next;
			lll->next = temp;
		}
		length++;
	}
};