【STL源码剖析读书笔记】自己实现stack之MyStack（底层用MyList）

MyList.h

#ifndef MY_LIST_H
#define MY_LIST_H

#include<memory>
//list的node结构
template<typename T>
struct list_node{
	typedef list_node<T>* pointer;
	pointer prev;
	pointer next;
	T data;
};
//list的iterator
template<typename T>
struct list_iterator{
	//list_iterator的嵌套型别定义
	typedef T value_type;
	typedef T* pointer;
	typedef const T* const_pointer;
	typedef T& reference;
	typedef const T& const_reference;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;
	typedef list_iterator<T> iterator;

	list_node<T>* node;//指向list的节点
	list_iterator(list_node<T>* p = nullptr) :node(p){}//构造函数

	reference operator*() const { return node->data; } //重载运算符*
	pointer operator->() const { return &(operator*()); } //重载运算符->
	iterator& operator++(){   //前++
		node = node->next;
		return *this;
	}
	iterator operator++(int){ //后++
		iterator tmp = *this;
		++*this;
		return tmp;
	}
	iterator& operator--(){ //前--
		node = node->prev;
		return *this;
	}
	iterator operator--(int){ //后--
		iterator tmp = *this;
		--*this;
		return tmp;
	}
	bool operator==(const iterator& x) const { return node == x.node; } //重载运算符==
	bool operator!=(const iterator& x) const { return node != x.node; } //重载运算符!=
};
//list
template<typename T>
class MyList{
public:
	//list的嵌套型别定义
	typedef T value_type;
	typedef T* pointer;
	typedef const T* const_pointer;
	typedef T& reference;
	typedef const T& const_reference;
	typedef list_iterator<T> iterator;
	typedef const list_iterator<T> const_iterator;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;
	typedef list_node<T>* link_type;
protected:
	link_type node; //一个指针可以表示整个环状双向链表
	std::allocator<list_node<T>> alloc;//空间分配器
public:
	//拷贝函数和析构函数
	MyList();
	MyList(size_type n, const T& value);
	template<typename InputIterator>
	MyList(InputIterator first, InputIterator last);
	~MyList();
	//拷贝控制函数
	MyList<T>(const MyList& lst);
	MyList<T>& operator=(const MyList& lst);
protected:
	void empty_initialize();
	link_type get_node(){ return alloc.allocate(1); }//配置一个节点
	void put_node(link_type p){ alloc.deallocate(p, 1); } //释放一个节点
	link_type create_node(const T& t){ //产生一个节点
		link_type p = get_node();
		new (&p->data) T(t); //定位new,在指定地址处构造对象
		return p;
	}
	void destroy_node(link_type p){ //销毁一个节点
		(&p->data)->~T();
		put_node(p);
	}
public:
	iterator begin(){ return iterator(node->next); }
	const_iterator begin() const { return iterator(node->next); }
	iterator end(){ return iterator(node); }
	const_iterator end() const { return iterator(node); }
	size_type size() const {
		size_type result = 0;
		link_type p = node->next;
		while (p != node){
			++result;
			p = p->next;
		}
		return result;
	}
	bool empty() const { return node->next == node; }
	reference front(){ return node->next->data; }
	reference back(){ return node->prev->data; }

	void push_back(const T& t);
	void pop_back();
	void push_front(const T& t);
	void pop_front();

	iterator insert(iterator position, const T& value);
	void insert(iterator position, size_type n, const T& value);
	iterator erase(iterator position);
	iterator erase(iterator first, iterator last);
	void remove(const T& value);
	void clear();

	void splice(iterator position, MyList& x);
	void splice(iterator position, MyList&, iterator i);
	void splice(iterator position, MyList&, iterator first, iterator last);
	void merge(MyList& x);
	void reverse();
	void swap(MyList& x);
	void sort();
protected:
	void transfer(iterator position, iterator first, iterator last);
};
template<typename T>
void MyList<T>::empty_initialize(){
	node = get_node();
	node->next = node->prev = node;
}
//默认构造函数
template<typename T>
MyList<T>::MyList(){
	empty_initialize();
}
//构造函数
template<typename T>
MyList<T>::MyList(size_type n, const T& value){
	empty_initialize();
	for (; n > 0; --n)
		insert(begin(), value);
}
//构造函数
template<typename T>
template<typename InputIterator>
MyList<T>::MyList(InputIterator first, InputIterator last){
	empty_initialize();
	for (InputIterator it = first; it != last; ++it)
		insert(end(), *it);
}
//析构函数
template<typename T>
MyList<T>::~MyList(){
	clear();
	destroy_node(node);
	node = nullptr;
}
//拷贝构造函数
template<typename T>
MyList<T>::MyList(const MyList& lst){
	empty_initialize();
	for (iterator it = lst.begin(); it != lst.end(); ++it)
		insert(end(), *it);
}
//拷贝赋值运算符
template<typename T>
MyList<T>& MyList<T>::operator=(const MyList& lst){
	if (this != &lst){
		clear();
		for (iterator it = lst.begin(); it != lst.end(); ++it)
			insert(end(), *it);
		return *this;
	}
}
//push_back(const T& t)
template<typename T>
void MyList<T>::push_back(const T& t){
	insert(end(), t);
}
//pop_back()
template<typename T>
void MyList<T>::pop_back(){
	iterator temp = end();
	erase(--temp);
}
//push_front(const T& t)
template<typename T>
void MyList<T>::push_front(const T& t){
	insert(begin(), t);
}
//pop_front()
template<typename T>
void MyList<T>::pop_front(){
	erase(begin());
}
//insert(iterator position, const T& value)
template<typename T>
typename MyList<T>::iterator MyList<T>::insert(iterator position, const T& value){
	link_type p = create_node(value);
	p->next = position.node;
	p->prev = position.node->prev;
	position.node->prev->next = p;
	position.node->prev = p;
	return iterator(p);
}
//insert(iterator position, size_type n, const T& value)
template<typename T>
void MyList<T>::insert(iterator position, size_type n, const T& value){
	while (n>0){
		insert(position, value);
		--n;
	}
}
//erase(iterator position)
template<typename T>
typename MyList<T>::iterator MyList<T>::erase(iterator position){
	link_type next_node = position.node->next;
	link_type pre_node = position.node->prev;
	pre_node->next = next_node;
	next_node->prev = pre_node;
	destroy_node(position.node);
	return iterator(next_node);
}
//erase(iterator first, iterator last)
template<typename T>
typename MyList<T>::iterator MyList<T>::erase(iterator first, iterator last){
	while (first != last)
		erase(first++);
	return last;
}
//remove(const T& value)
template<typename T>
void  MyList<T>::remove(const T& value){
	iterator first = begin();
	iterator last = end();
	while (first != last){
		iterator next = first;
		++next;
		if (*first == value)
			erase(first);
		first = next;
	}
}
//clear()
template<typename T>
void  MyList<T>::clear(){
	//link_type cur = (link_type)node->next;  //STL源码版本
	//while (cur != node){
	//	link_type temp = cur;
	//	cur = (link_type)cur->next;
	//	destroy_node(temp);
	//} 
	//node->next = node; //恢复原始状态
	//node->prev = node;
	iterator first = begin(); //我觉得用erase()也可完成clear()函数
	iterator last = end();
	while (first != last){
		iterator next = first;
		++next;
		erase(first);
		first = next;
	}
}
//transfer(iterator position, iterator first, iterator last)
template<typename T>
void  MyList<T>::transfer(iterator position, iterator first, iterator last){
	link_type first_node = first.node;
	link_type before_last_node = last.node->prev;
	first_node->prev->next = last.node;
	last.node->prev = first_node->prev;
	position.node->prev->next = first_node;
	first_node->prev = position.node->prev;
	before_last_node->next = position.node;
	position.node->prev = before_last_node;
}
//splice(iterator position, MyList<T>& x)
template<typename T>
void  MyList<T>::splice(iterator position, MyList& x){
	if (!x.empty())
		transfer(position, x.begin(), x.end());
}
//splice(iterator position, MyList<T>& x, iterator i)
template<typename T>
void  MyList<T>::splice(iterator position, MyList&, iterator i){
	iterator j = i;
	++j;
	if (position == i || position == j) return;
	transfer(position, i, j);
}
//splice(iterator position, MyList& x, iterator first, iterator last)
template<typename T>
void  MyList<T>::splice(iterator position, MyList&, iterator first, iterator last){
	if (first != last)
		transfer(position, firs, last);
}
//merge(MyList<T>& x)
template<typename T>
void  MyList<T>::merge(MyList& x){
	iterator first1 = begin();
	iterator last1 = end();
	iterator first2 = x.begin();
	iterator last2 = x.end();
	while (first1 != last1 && first2 != last2){
		if (*first2 < *first1){
			iterator next = first2;
			transfer(first1, first2, ++next);
			first2 = next;
		}
		else
			++first1;
	}
	if (first2 != last2)
		transfer(last1, first2, last2);
}
//reverse();
template<typename T>
void  MyList<T>::reverse(){
	if (node->next == node || node->next->next == node)
		return;
	iterator first = begin();
	++first;
	while (first != end()){
		iterator old = first;
		transfer(begin(), old, ++first);
	}
}
//swap(MyList& x)
template<typename T>
void MyList<T>::swap(MyList& x){
	if (node != x.node){
		link_type temp = node;
		node = x.node;
		x.node = temp;
	}
}
//sort()
template<typename T>
void MyList<T>::sort(){
	if (node->next == node || node->next->next == node)
		return;
	MyList<T> carry;
	MyList<T> counter[64];
	int fill = 0;
	while (!empty()){
		carry.splice(carry.begin(), *this, begin());
		int i = 0;
		while (i < fill&&!counter[i].empty()){
			counter[i].merge(carry);
			carry.swap(counter[i++]);
		}
		carry.swap(counter[i]);
		if (i == fill)
			++fill;
	}
	for (int i = 1; i < fill; ++i)
		counter[i].merge(counter[i - 1]);
	swap(counter[fill - 1]);

}

#endif

MyStack.h

#ifndef MY_STACK_H
#define MY_STACK_H
#include"MyList.h"

template<typename T,typename Sequence=MyList<T>>
class MyStack{
private:
	Sequence lst;
public:
	bool empty()const{ return lst.empty(); }
	int size()const{ return lst.size(); }
	T top(){ return lst.back(); }

	void push(const T& t){
		lst.push_back(t);
	}
	void pop(){
		lst.pop_back();
	}
};

#endif

mai.cpp

#include"MyStack.h"
#include<iostream>
using namespace std;

int main(){
	MyStack<int> stk;
	cout << (stk.empty() ? "empty" : "not empty") << endl;//empty

	for (int i = 0; i != 5; ++i)
		stk.push(i);  
	cout << "top:" << stk.top() << endl; //4
	cout << "size:" << stk.size() << endl;//5

	stk.pop();
	cout << "top:" << stk.top() << endl;//3
	cout << "size:" << stk.size() << endl;//4

	system("pause");
	return 0;
}