数据结构-单链表-类定义C++

原理可访问https://www.cnblogs.com/yang901112/p/11674333.html

头文件

#ifndef RLIST_H
#define RLIST_H
#include <iostream>

template <class T> class List;

template <class T>
class ListNode
{
    friend class List<T>;
public:
    ListNode() { next = 0; }
    ListNode(T el, ListNode* ptr = 0) {
        data = el; next = ptr;
    }
private:
    T data;
    ListNode *next;
};

template <class T>
class List
{
public:
    List() { 
        head = 0;
        head = tail = 0; }
    ~List();
    int isEmpty() {
        return head == 0;
    }
    void addToHead(T);  //从头插入结点
    void addToTail(T);  //从尾部插入节点
    void disPlay() const;
    T deleteFromHead();  //从头删除结点//若不需要返回值可以使用void
    T deleteFromTail();  //从尾部删除节点
    void deleteNode(T);  //按值删除结点
    bool isInList(T) const;  //判断值是否在链表里
    void Invert();  //反转链表
private:
    ListNode<T> *head, *tail;
};

template <class T>
List<T>::~List() {
    for (ListNode<T> *p; !isEmpty();) {
        p = head->next;
        delete head;
        head = p;
    }
}

template <class T>
void List<T>::addToHead(T el) {
    head = new ListNode<T>(el, head);
    if (tail == 0)
        tail = head;
}

template <class T>
void List<T>::addToTail(T el) {
    if (tail != 0) {
        tail->next = new ListNode<T>(el);
        tail = tail->next;
    }
    else head = tail = new ListNode<T>(el);
}

template <class T>
T List<T>::deleteFromHead() {
    T el = head->data;
    ListNode<T> *tmp = head;
    if(head==tail)
    {
        head = tail = 0;
    }
    else head = head->next;
    delete tmp;
    return el;
}

template <class T>
T List<T>::deleteFromTail() {
    T el = tail->data;
    if(head==tail)
    {
        delete head;
        head = tail = 0;
    }
    else {
        ListNode<T> *tmp;
        for (tmp = head; tmp->next != tail; tmp = tmp->next);
        delete tail;
        tail = tmp;
        tail->next = 0;
    }
    return el;
}

template <class T>
void List<T>::deleteNode(T el) {
    ListNode<T> *previous = 0;
    ListNode<T> *current;
    for (current = head; current && current->data != el;
        previous = current, current = current->next);
    if (current)
    {
        if (previous) { previous->next = current->next; }
        else head = head->next;
        delete current;
    }
}

/*****************************************/
//template <class T>
//bool List<T>::isInList(T el) const {
//    bool flag = false;
//    ListNode<T> *tmp;
//    tmp = head->next;
//    while (tmp) {
//        if (tmp->data == el) {
//            flag = true;
//            break;
//        }
//        tmp = tmp->next;
//    }
//    return flag;
//}

//可以使用for循环代替while代码可以简洁一些
template <class T>
bool List<T>::isInList(T el) const {
    ListNode<T> *tmp;
    for (tmp = head; tmp && tmp->data != el; tmp = tmp->next);
    return tmp != 0;
}
/*****************************************/

template <class T>
void List<T>::Invert() {
    ListNode<T> *p = head, *q = 0;
    while (p)
    {
        ListNode<T> *r = q; q = p;
        p = p->next;
        q->next = r;
    }
    head = q;
}


template <class T>
void List<T>::disPlay() const{
    //ListNode<T>  *p;
    //p = head;
    //while (p)
    //{
    //    std::cout << p->data;
    //    if (p->next) { std::cout << "->"; } //就是仅在数字之间加"->"
    //    p = p->next;
    //}
    for (ListNode<T> *current = head; current; current = current->next)
    {
        std::cout << current->data;
        if (current->next) std::cout << "->";
    }
    std::cout << std::endl;
}

#endif

源文件

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

int main()
{
    cout << "测试" << endl;
    List<int> ilist;
    ilist.addToTail(1);
    ilist.addToTail(2);
    ilist.addToTail(3);
    ilist.addToTail(4);
    ilist.disPlay();
    ilist.deleteFromHead();
    ilist.disPlay();

    List<int> ilist2;
    ilist2.addToHead(5);
    ilist2.addToHead(6);
    ilist2.addToHead(7);
    ilist2.addToHead(8);
    ilist2.disPlay();
    cout << ilist2.isInList(5) << endl;
    ilist2.deleteFromTail();
    ilist2.disPlay();
    cout << ilist2.isInList(5) << endl;
    
    List<char> charlist1;
    charlist1.addToTail('a');
    charlist1.addToTail('b');
    charlist1.addToTail('c');
    charlist1.addToTail('d');
    charlist1.disPlay();
    charlist1.Invert();
    charlist1.disPlay();
    charlist1.deleteNode('c');
    charlist1.disPlay();
    charlist1.deleteNode('e'); //虽然'e'不存在，但是不影响
    charlist1.disPlay();



    return 0;
}