my_list

記錄資料結構連結串列學習過程（手寫list）

#include <iostream>
#include<bits/stdc++.h>
using namespace std;

typedef int Rank;
template<typename T> struct ListNode{
    T data;           //資料域
    ListNode<T> *prev;//前驅
    ListNode<T> *next;//後繼

    ListNode() {};
    ListNode(T e,ListNode p=NULL,ListNode q=NULL)
    :data(e),prev(p),next(q) {}//預設構造(方便賦值)
};

template<typename T> class my_list{
private:
    int _size;          //元素個數
    ListNode<T> *header;//頭指標
    ListNode<T> *trailer;//尾指標
    void init();    //初始化

public:
    my_list(){init();}//預設構造
    ~my_list();      //析構

    T& operator[] (Rank ) const;         //過載[]運算子
    Rank size() const {return _size;}    //大小
    bool empty() const {return _size<=0;}//判斷是否為空
    void my_clear();                     //清空
    ListNode<T>* getHeader(){return header;}  //返回頭節點
    ListNode<T>* getTrailer(){return trailer;}//返回尾節點

    ListNode<T>* insert_prev(ListNode<T> *,int );  //頭插法
    ListNode<T>* insert_next(ListNode<T> *,int );  //尾插法
    T my_remove(ListNode<T> *);                    //刪除
    ListNode<T>* my_find(T const& )const;          //查詢
};

template<typename T> T& my_list<T>::operator[] (Rank r)const{
    ListNode<T> *p=header->next;
    while(0<r--){
        p=p->next;
    }
    return p->data;
}

template<typename T> void my_list<T>::init(){
    header=new ListNode<T>;
    trailer=new ListNode<T>;
    header->prev=NULL;
    header->next=trailer;
    trailer->prev=header;
    trailer->next=NULL;
    _size=0;
}

template<typename T> ListNode<T>* my_list<T>::insert_prev(ListNode<T> *p,int e){
    ListNode<T> *temp=new ListNode<T>;
    temp->data=e;
    temp->prev=p->prev;
    temp->next=p;
    p->prev->next=temp;
    p->prev=temp;
    _size++;
    return temp;
}

template<typename T> ListNode<T>* my_list<T>::insert_next(ListNode<T> *p,int e){
    ListNode<T> *temp=new ListNode<T>;
    temp->data=e;
    temp->prev=p;
    temp->next=p->next;
    p->next->prev=temp;
    p->next=temp;
    _size++;
    return temp;
}

template<typename T> T my_list<T>::my_remove(ListNode<T> *p){
    p->next->prev=p->prev;
    p->prev->next=p->next;
    T e=p->data;
    delete p;
    _size--;
    return e;
}

template<typename T> void my_list<T>::my_clear(){

    while(0<_size--){
        my_remove(header->next);
    }
}

template<typename T> my_list<T>::~my_list(){
    my_clear();
    delete header;
    delete trailer;
}

template<typename T> ListNode<T>* my_list<T>::my_find(T const& e)const{
    ListNode<T> *p=header;
    int n=_size;
    while(0<n--){
        if(e == (p=p->next)->data) return p;

    }
    return NULL;
}

int main(){
    my_list<int> L;
    ListNode<int> *h=L.getHeader();
    for(int i=0;i<10;i++){
        L.insert_next(h,i);
        h=h->next;
    }

    for(ListNode<int> *p=L.getHeader()->next;p!=L.getTrailer();p=p->next)cout<<p->data<<" ";
    cout<<endl;

    cout<<L.size()<<endl;
    L.my_remove(L.my_find(5));
    cout<<L.size()<<endl;
    
    for(ListNode<int> *p=L.getHeader()->next;p!=L.getTrailer();p=p->next)cout<<p->data<<" ";
    cout<<endl;

    cout<<L.empty()<<endl;
    L.my_clear();
    cout<<L.empty()<<endl;
    
    return 0;
}

效果展示