尾插法链表

Posted 2021-03-05 yang901112

不使用循环，采用头尾指针，不带有头结点，我这里只是简易的输出，并没有写专用的迭代器。

  1 #include <iostream>
  2 
  3 using namespace std;
  4 
  5 template<class T> class MyList;
  6 
  7 template<class T>
  8 class ListNode
  9 {
 10     friend class MyList<T>;
 11 private:
 12     T data;
 13     ListNode *Link;
 14     ListNode(const T &thedata){data = thedata; Link=0;}
 15     ListNode(){}
 16 };
 17 
 18 template<class T>
 19 class MyList
 20 {
 21 public:
 22     MyList(){first = new ListNode<T>;first->Link=NULL;tail=first;}
 23     ~MyList(){MakeEmpty();}
 24     void MakeEmpty();
 25     bool IsEmpty();
 26     void Insert(const T &);
 27     void Delete(const T &);
 28     void Invert();
 29     void Concatenate(MyList<T>);
 30     void Show();
 31 private:
 32     ListNode<T> *first;
 33     ListNode<T> *tail;
 34 };
 35 
 36 template<class T>
 37 bool MyList<T>::IsEmpty()
 38 {
 39     return first == 0;
 40 }
 41 
 42 template<class T>
 43 void MyList<T>::MakeEmpty()
 44 {
 45     ListNode<T> *p=first;
 46     while(first)
 47     {
 48         p = first;
 49         first = first->Link;
 50         delete p;
 51     }
 52 }
 53 
 54 template<class T>
 55 void MyList<T>::Insert(const T &x)
 56 {
 57     ListNode<T> *newNode = new ListNode<T>(x);
 58     newNode->Link=tail->Link;
 59     tail->Link = newNode;
 60     tail = newNode;
 61 }
 62 
 63 template<class T>
 64 void MyList<T>::Delete(const T &k)
 65 {
 66     if(IsEmpty()) return;
 67     ListNode<T> *previous=0;
 68     ListNode<T> *current;
 69     for(current=first;current&&current->data!=k;
 70         previous=current,current=current->Link);
 71     if(current)
 72     {
 73         if(previous) previous->Link=current->Link;
 74         else first->Link=tail;
 75         delete current;
 76     }
 77 }
 78 
 79 template<class T>
 80 void MyList<T>::Invert()
 81 {
 82     ListNode<T> *p=first->Link, *q=0;
 83     while(p)
 84     {
 85         ListNode<T> *r = q; q = p;
 86         p = p->Link;
 87         q->Link = r;
 88     }
 89     first->Link = q;
 90 }
 91 
 92 template<class T>
 93 void MyList<T>::Concatenate(MyList<T> List2)
 94 {
 95     if(!first) {first = List2.first;}
 96     if(List2.first)
 97     {
 98         ListNode<T> *p;
 99         for(p=first; p->Link; p=p->Link);
100         p->Link = List2.first->Link;
101     }
102 }
103 
104 
105 template<class T>
106 void MyList<T>::Show()
107 {
108     ListNode<T> *current;
109     for(current=first->Link; current; current=current->Link)
110     {
111         cout << current->data;
112         if(current->Link) cout << "->";
113     }
114     cout << endl;
115 }
116 
117 int main()
118 {
119     MyList<int> intlist;
120     intlist.Insert(5);
121     intlist.Insert(15);
122     intlist.Insert(25);
123     intlist.Insert(35);
124     intlist.Invert();
125     MyList<int> intlist2;
126     intlist2.Insert(45);
127     intlist.Concatenate(intlist2);
128     intlist.Show();
129     intlist.Delete(35);
130     intlist.Delete(25);
131     intlist.Delete(15);
132     intlist.Delete(6);
133 
134     intlist.Show();
135 //    cout << "Hello world!" << endl;
136     return 0;
137 }