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 = ; }
     ListNode(T el, ListNode* ptr = ) {
         data = el; next = ptr;
     }
 private:
     T data;
     ListNode *next;
 };
 
 template <class T>
 class List
 {
 public:
     List() {
         head = ;
         head = tail = ; }
     ~List();
     int isEmpty() {
         return head == ;
     }
     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 == )
         tail = head;
 }
 
 template <class T>
 void List<T>::addToTail(T el) {
     if (tail != ) {
         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 = ;
     }
     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 = ;
     }
     else {
         ListNode<T> *tmp;
         for (tmp = head; tmp->next != tail; tmp = tmp->next);
         delete tail;
         tail = tmp;
         tail->next = ;
     }
     return el;
 }
 
 template <class T>
 void List<T>::deleteNode(T el) {
     ListNode<T> *previous = ;
     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 != ;
 }
 /*****************************************/
 
 template <class T>
 void List<T>::Invert() {
     ListNode<T> *p = head, *q = ;
     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();
     ilist.addToTail();
     ilist.addToTail();
     ilist.addToTail();
     ilist.disPlay();
     ilist.deleteFromHead();
     ilist.disPlay();
 
     List<int> ilist2;
     ilist2.addToHead();
     ilist2.addToHead();
     ilist2.addToHead();
     ilist2.addToHead();
     ilist2.disPlay();
     cout << ilist2.isInList() << endl;
     ilist2.deleteFromTail();
     ilist2.disPlay();
     cout << ilist2.isInList() << 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 ;
 }