数据结构-单链表-类定义2-C++

  1 #ifndef LIST_H
  2 #define LIST_H
  3 #include <iostream>
  4 
  5 template <class Type> class List;          //前置声明
  6 template <class Type> class ListIterator;  //前置声明
  7 
  8 //创建结点类
  9 template <class Type>  //类模板
 10 class ListNode
 11 {
 12     friend class List<Type>;           //友元函数--29行
 13     friend class ListIterator<Type>;   //友元函数--46行
 14 private:
 15     Type data;
 16     ListNode *link;
 17     ListNode(Type);
 18 };
 19 
 20 template <class Type>
 21 ListNode<Type>::ListNode(Type element)  //创建头结点
 22 {
 23     data = element;
 24     link = 0;
 25 }
 26 
 27 //创建链表类
 28 template <class Type>
 29 class List
 30 {
 31     friend class ListIterator<Type>;  //友元函数--46行
 32 public:
 33     List() { first=tail= 0; }; 
 34     void Insert(Type);      //头插法
 35     void Inserttail(Type);  //尾插法
 36     void Delete(Type);      //按值删除元素
 37     void Invert();          //反转链表
 38     void Concatenate(List<Type>);  //连接链表
 39     void Show();  //显示链表做测试用，创建迭代器后可以不用它显示
 40 
 41 private:
 42     ListNode<Type> *first, *tail;  // 创建头指针
 43 };
 44 
 45 /**************************************************************/
 46 //创建迭代器类
 47 template <class Type>
 48 class ListIterator
 49 {
 50 public:
 51     ListIterator(const List<Type>& l):list(l),current(l.first){}
 52     bool NotNull();
 53     bool NextNotNull();
 54     Type* First();
 55     Type* Next();
 56 private:
 57     const List<Type> &list;
 58     ListNode<Type>* current;
 59 };
 60 
 61 template <class Type>
 62 bool ListIterator<Type>::NotNull()
 63 {
 64     if (current) return true;
 65     else return false;
 66 }
 67 
 68 template <class Type>
 69 bool ListIterator<Type>::NextNotNull()
 70 {
 71     if (current && current->link) return true;
 72     else return false;
 73 }
 74 
 75 template <class Type>
 76 Type* ListIterator<Type>::First()
 77 {
 78     if (list.first) return &list.first->data;
 79     else return 0;
 80 }
 81 
 82 template <class Type>
 83 Type* ListIterator<Type>::Next()
 84 {
 85     if (current)
 86     {
 87         current = current->link;
 88         return &current->data;
 89     }
 90     else return 0;
 91 }
 92 /**************************************************************/
 93 
 94 // 前插法
 95 template <class Type>
 96 void List<Type>::Insert(Type k)
 97 {
 98     ListNode<Type> *newnode = new ListNode<Type>(k);  // 21行，新建结点并为data域赋值k
 99     
100     //下面两行的意义就是头插法，将新建立的结点从头插入
101     newnode->link = first;
102     first = newnode;
103 }
104 
105 template <class Type>
106 void List<Type>::Inserttail(Type k)
107 {
108     if (tail != 0) {
109         tail->link = new ListNode<Type>(k);
110         tail = tail->link;
111     }
112     else first = tail = new ListNode<Type>(k);
113 }
114 
115 template <class Type>
116 void List<Type>::Delete(Type k)
117 {
118     ListNode<Type> *previous = 0;
119     ListNode<Type> *current;
120     for (current = first; current && current->data != k;
121         previous = current, current = current->link);
122 
123     if (current)
124     {
125         if (previous) previous->link = current->link;
126         else first = first->link;
127         delete current;
128     }
129 }
130 
131 template <class Type>
132 void List<Type>::Invert()
133 {
134     ListNode<Type> *p = first, *q = 0;
135     while (p)
136     {
137         ListNode<Type> *r = q; q = p;
138         p = p->link;
139         q->link = r;
140     }
141     first = q;
142 }
143 
144 template <class Type>
145 void List<Type>::Concatenate(List<Type> b)
146 {
147     if (!first) { first = b.first; return; }
148     if (b.first)
149     {
150         ListNode<Type> *p;
151         for (p = first; p->link; p = p->link);
152         p->link = b.first;
153     }
154 }
155 
156 template <class Type>
157 void List<Type>::Show()
158 {
159     for (ListNode<Type> *current = first; current; current = current->link)
160     {
161         std::cout << current->data;
162         if (current->link) std::cout << "->";
163     }
164     std::cout << std::endl;
165 }
166 
167 #endif

 1 #include<iostream>
 2 #include"List.h"
 3 using namespace std;
 4 
 5 int main()
 6 {
 7     cout << "测试" << endl;
 8     cout << "自建的迭代器" << endl;
 9     List<int> intList;
10     intList.Insert(5);
11     intList.Insert(15);
12     intList.Insert(25);
13     intList.Insert(35);
14 
15     /**************************************************************/
16     //可以先注释这段迭代器输出
17     ListIterator<int> li(intList);             
18     if (li.NotNull())   
19     {
20         cout << *li.First();
21         while (li.NextNotNull())
22             cout << "->" << *li.Next();
23         cout << endl;
24     }
25     /**************************************************************/
26 
27     intList.Show();
28     intList.Invert();
29     intList.Show();
30 
31     intList.Delete(15);
32     intList.Show();
33     intList.Delete(20);
34     intList.Show();
35 
36     List<char> charList;
37     charList.Insert(‘a‘);
38     charList.Insert(‘b‘);
39     charList.Insert(‘c‘);
40     charList.Insert(‘d‘);
41     charList.Show();
42     charList.Invert();
43     charList.Show();
44 
45     List<char> char2List;
46     char2List.Insert(‘e‘);
47     char2List.Insert(‘f‘);
48     char2List.Show();
49     char2List.Invert();
50     char2List.Show();
51 
52     charList.Concatenate(char2List);
53     charList.Show();
54 
55     List<int> intList2;
56     intList2.Inserttail(1);
57     intList2.Inserttail(2);
58     intList2.Inserttail(3);
59     intList2.Inserttail(4);
60     intList2.Show();
61 
62     intList.Concatenate(intList2);
63     ListIterator<int> li2(intList);
64     if (li2.NotNull())
65     {
66         cout << *li2.First();
67         while (li2.NextNotNull())
68             cout << "->" << *li2.Next();
69         cout << endl;
70     }
71 
72     return 0;
73 }