自己实现STL容器——list

通过自己实现STL的list容器，相信大家会对list容器以及相关函数有进一步的了解

#include <iostream>
using namespace std;

class NotElementException:public exception{
public:
	NotElementException(const char *info="没有元素"):errinfo(info){}
	~NotElementException()throw(){}
	const char * what()throw(){
		return errinfo.c_str();	
	}
private:
	string errinfo;
};

class InvalidIteratorException:public exception{
public:
	InvalidIteratorException(const char *info="无效迭代器指针"):errinfo(info){}
	~InvalidIteratorException()throw(){}
	const char* what()throw(){
		return errinfo.c_str();
	}
private:
	string errinfo;
};

template<typename T>
class List{
private:
	class Node{
	public:
		T data;
		Node *prev;
		Node *next;
	public:
		Node():prev(NULL),next(NULL){}
		Node(T data,Node *prev=NULL,Node *next=NULL):
			data(data),prev(prev),next(next){}
	};
	Node *head;
	Node *tail;
public:
	List(){
		head = new Node();
		tail = new Node();
		head->next = tail;
		tail->prev = head;
	}
	size_t size(){
		Node *node = head->next;
		size_t s = 0;
		while(node != tail){
			node = node->next;
			++s;
		}
		return s;
	}
	bool empty(){
		return head->next == tail && tail->prev == head;	
	}
	void clear(){
		Node *node = head->next;
		while(node != tail){
			Node *next = node->next;
			delete node;
			node = next;
		}
		head->next = tail;
		tail->prev = head;
	}
	~List(){
		clear();	
		delete head;
		delete tail;
		head = NULL;
		tail = NULL;
	}
	void push_front(T data){
		Node *node = new Node(data,head,head->next);
		head->next->prev = node;
		head->next = node;
	}
	void push_back(T data){
		Node *node = new Node(data,tail->prev,tail);
		tail->prev->next = node;
		tail->prev = node;
	}
	List(const List& lt){
		head = new Node();
		tail = new Node();
		head->next = tail;
		tail->prev = head;
		Node *node = (lt.head)->next;
		while(node != lt.tail){
			push_back(node->data);
			node = node->next;
		}
	}
	//l1 = l2;
	List& operator=(const List& lt){
		if(this != &lt){
			clear();//清空自己
			Node *node = (lt.head)->next;
			while(node != lt.tail){//遍历lt
				push_back(node->data);
				node = node->next;
			}
		}	
		return *this;
	}

	class iterator{
	public:
		Node *node;
	public:
		iterator(Node *node):node(node){};
		iterator& operator++(){
			node = node->next;
			return *this;
		}
		iterator operator++(int){
			iterator it(*this);
			node = node->next;
			return it;
		}
		iterator& operator--(){
			node = node->prev;
			return *this;
		}
		iterator operator--(int){
			iterator it(*this);
			node = node->prev;
			return it;
		}
		bool operator==(const iterator& it)const{
			return node == it.node;	
		};
		bool operator!=(const iterator& it)const{
			return node != it.node;	
		}
		T& operator*(void){
			return node->data;	
		}
	};

	iterator begin(){
		return iterator(head->next);	
	}
	iterator end(){
		return iterator(tail);	
	}
	void pop_front(){
		if(empty()){
			throw NotElementException();	
		}	
		Node *node = head->next;
		head->next->next->prev = head;
		head->next = head->next->next;
		delete node;
	}
	void pop_back(){
		if(empty()){
			throw NotElementException();	
		}
		Node *node = tail->prev;
		tail->prev->prev->next = tail;
		tail->prev = tail->prev->prev;
		delete node;
	}
	//删除it所指向的节点
	iterator erase(iterator& it){
		if(it == head || it == tail){
			throw InvalidIteratorException();	
		}
		Node *next = it.node->next;
		it.node->prev->next = it.node->next;
		it.node->next->prev = it.node->prev;
		delete it.node;
		it.node = next;
		return it;
	}
	//it之前插入
	iterator insert(iterator& it,T data){
		if(it.node == head){
			throw InvalidIteratorException();	
		}
		Node *node = new Node(data,it.node->prev,it.node);
		it.node->prev->next = node;
		it.node->prev = node;
		it.node = node;
		return it;
	}
};

template<typename IT>
void print(IT beg,IT end){
	while(beg != end){
		cout << *beg << " ";
		++beg;
	}	
	cout << endl;
}
int main(){
	List<int> l1;
	l1.push_back(1);
	l1.push_back(3);
	l1.push_back(5);
	l1.push_back(7);
	l1.push_back(9);
	l1.push_front(2);
	l1.push_front(4);
	l1.push_front(6);
	l1.push_front(8);
	l1.push_front(10);
	l1.push_front(0);
	List<int>::iterator it = l1.begin();
	for(;it != l1.end(); ++it){
		cout << *it << " ";	
	}
	cout << endl;
	l1.pop_front();
	l1.pop_back();
	print(l1.begin(),l1.end());
	it = l1.begin();
	++it;
	++it;
	++it;
	l1.insert(it,100);
	print(l1.begin(),l1.end());
	return 0;	
}