C++list類模擬實現
阿新 • • 發佈：2019-01-14
MyList.h
#ifndef __LIST_H__ #define __LIST_H__ #include<iostream> #include<stdlib.h> #include<assert.h> using namespace std; namespace TJ { template <class T> struct ListNode { //匿名物件T ListNode(const T& data = T()) :_data(data), _next(nullptr), _prev(nullptr) { } T _data; ListNode<T>* _next; ListNode<T>* _prev; }; template <class T,class Ref,class Ptr> struct ListIterator { typedef ListNode<T> Node; typedef ListIterator<T,Ref,Ptr> Iterator; ListIterator(Node* node) :_node(node) { } ListIterator(const Iterator& i) :_node(i._node) { } Ref operator*() { return _node->_data; } Ptr operator->() { return &(operator*()); } //前置++ Iterator operator++() { _node = _node->_next; return *this; } //後置++ Iterator operator++(int) { Iterator i(*this); _node = _node->_next; return i; } //前置-- Iterator operator--() { _node = _node->_prev; return *this; } //後置-- Iterator operator--(int) { Iterator i(*this); _node = _node->_prev; return i; } bool operator!=(const Iterator& i) { return _node != i._node; } bool operator==(const Iterator& i) { return _node == i._node; } Node* _node; }; template<class T> class List { typedef ListNode<T> Node; public: typedef ListIterator<T,T&,T*> Iterator; typedef ListIterator<T,const T&,const T*> Const_Iterator; //建構函式 //構造空的list List():_head(new Node) { _head->_next = _head; _head->_prev = _head; } //構造的list中包含n個值為data的元素 List(int n, const T& data = new T()) :_head(new Node) { _head->_next = _head; _head->_prev = _head; for (int i = 0; i < n; i++) { PushBack(data); } } ///用[first, last)區間中的元素構造list template<class Iterator> List(Iterator first, Iterator last) :_head(new Node) { _head->_next = _head; _head->_prev = _head; while (first != last) { PushBack(*first); *first++; } } //拷貝建構函式 List(List<T>& l) :_head(new Node) { _head->_next = _head; _head->_prev = _head; List<T> tmp(l.begin(), l.end()); swap(_head, l._head); } //賦值運算子過載 List<T>& operator=(List<T>& l) { if (this != &l) { List<T> tmp(l); swap(_head, l._head); } return *this; } ~List() { Clear(); delete _head; _head = nullptr; } void Clear() { Node* cur = _head->_next; while (cur != _head) { _head = cur->_next; delete cur; cur = _head; } _head->_next = _head; _head->_prev = _head; } Iterator begin() { return Iterator(_head->_next); } Iterator end() { return Iterator(_head); } void PushBack(const T& data) { /*Node* tail = _head->_prev; Node* newnode = new Node(data); tail->_next = newnode; newnode->_prev = tail; newnode->_next = _head; _head->_prev = newnode;*/ Insert(end(), data); } void PopBack() { /*Node* del = _head->_prev; if (del != _head) { Node* tail = del->_prev; _head->_prev = tail; tail->_next = _head; delete del; del = nullptr; }*/ Erase(--end()); } void PushFront(const T& data) { /*Node* front = _head->_next; Node* newnode = new Node(data); _head->_next = newnode; newnode->_prev = _head; newnode->_next = front; front->_prev = newnode;*/ Insert(begin(), data); } void PopFront() { /*Node* second = _head->_next->_next; _head->_next = second; delete second->_prev; second->_prev = _head;*/ Erase(begin()); } void Insert(Iterator pos, const T& data) { Node* cur = pos._node; Node* pre = cur->_prev; Node* newnode = new Node(data); cur->_prev = newnode; newnode->_next = cur; newnode->_prev = pre; pre->_next = newnode; } void Erase(Iterator pos) { Node* del = pos._node; Node* next = del->_next; Node* pre = del->_prev; pre->_next = next; next->_prev = pre; delete del; del = nullptr; } T& Front() { return _head->_next->_data; } T& Back() { return _head->_prev->_data; } Iterator Find(const T& data) { Node* cur = _head->_next; while (cur != _head) { if (cur->_data == data) { return Iterator(cur); } cur = cur->_next; } } size_t Size() const//O(n)不要經常呼叫 { size_t count = 0; Node* cur = _head->_next; while (cur != _head) { ++count; cur = cur->_next; } return count; } bool Empty() { return _head->_next == _head; } void Resize(int newsize, const T& data = T()) { int oldsize = Size(); if (newsize < oldsize) { for (int i = 0; i < (oldsize - newsize); i++) { PopBack(); } } else { for (int i = 0; i < (newsize - oldsize); i++) { PushBack(data); } } } private: Node* _head; }; } #endif
MyList.cc
#include"List.h" #include<vector> void test1() { TJ::List<int> list1; list1.PushBack(1); list1.PushBack(2); list1.PushBack(3); list1.PushBack(4); list1.PushBack(5); list1.PopFront(); TJ::List<int>::Iterator pos = list1.Find(2); list1.Insert(pos, 9); TJ::List<int>::Iterator it = list1.begin(); TJ::List<int>::Iterator pos1 = list1.Find(4); list1.Erase(pos1); while (it != list1.end()) { cout << *it << endl; ++it; } } void test0() { TJ::List<int> list1; list1.PushBack(1); list1.PushBack(1); list1.PushBack(1); list1.PushBack(1); list1.PushBack(1); TJ::List<int>::Iterator it = list1.begin(); while (it != list1.end()) { cout << *it << endl; ++it; } //拷貝測試 TJ::List<int> list2(list1); TJ::List<int>::Iterator it2 = list2.begin(); while (it2 != list2.end()) { cout << *it2 << endl; ++it2; } //迭代器區間構造 TJ::List<int> list4(list1.begin(), list1.end()); TJ::List<int>::Iterator it4 = list4.begin(); while (it4 != list4.end()) { cout << *it4 << endl; ++it4; } } void test2() { TJ::List<int> l; l.PushBack(1); l.PushBack(2); l.PushBack(3); l.PushBack(4); l.PushBack(4); l.PushBack(4); cout << l.Size() << endl; cout << l.Empty() << endl; l.Resize(9,1); TJ::List<int>::Iterator it = l.begin(); while (it != l.end()) { cout << *it << endl; ++it; } } void test3() { TJ::List<int> l; l.PushBack(1); l.PushBack(2); l.PushBack(3); l.PushBack(4); TJ::List<int>::Iterator it = l.begin(); ++it; cout << *(it++) << endl; cout << *(it--) << endl; } void test4() { int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; TJ::List<int> l(arr, arr + sizeof(arr) / sizeof(arr[0])); TJ::List<int>::Iterator it = l.begin(); while (it != l.end()) { cout << *it << endl; ++it; } } int main() { test4(); system("pause"); return 0; }