倒数第K个数和中间数。
自己编码能力还不行，要多多加油才行啊！！！
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1 #include<iostream>
2 #include<string>
3 using namespace std;
4
5 template<class Type> class List
6 {
7 private:
8 template<class T> class LinkNode
9 {
10 public:
11 LinkNode<Type> *link;
12 Type data;
13 LinkNode(LinkNode<Type>* ptr=NULL)
14 {
15 link=ptr;
16 }
17 LinkNode(const Type& item,LinkNode<Type>* ptr=NULL)
18 {
19 data=item;
20 link=ptr;
21 }
22 };
23 LinkNode<Type>* first;
24 public:
25 List()
26 {
27 first=new LinkNode<Type>; //想一下为什么不能写成LinkNode<Type>* ptr=NULL; first=ptr;
28 }
29
30 void inputRear(const Type& endtag)
31 {
32 LinkNode<Type> *newNode,*curr;
33 curr=first;
34 Type val;
35 cin>>val;
36 while(val!=endtag)
37 {
38 newNode=new LinkNode<Type>(val);
39 curr->link=newNode;
40 curr=curr->link;
41 cin>>val;
42 }
43 }
44
45 void output()
46 {
47 LinkNode<Type> *curr=first->link;
48 while(curr!=NULL)
49 {
50 cout<<curr->data<<"";
51 curr=curr->link;
52 }
53 cout<<endl;
54 }
55
56
57 void findReciprocalOfNum(int num) //需要遍历两次
58 {
59 int count=0;
60 LinkNode<Type> *curr1,*curr2;
61 curr1=curr2=first;
62 while(curr1->link!=NULL)
63 {
64 count++;
65 curr1=curr1->link;
66 }
67 if(count<num)
68 {
69 cout<<"链表长度不够，找不到倒数为第"<<num<<"个元素！";
70 return;
71 }
72 count=count-num+1;
73 while(count)
74 {
75 curr2=curr2->link;
76 count--;
77 }
78 cout<<"倒数第"<<num<<"个元素为："<<curr2->data<<endl;
79 }
80
81 void findReciprocalOfNum2(int num)
82 {
83 LinkNode<Type> *flag,*loop;
84 flag=loop=first;
85 for(int i=0;i<num;i++)
86 {
87 loop=loop->link;
88 if(loop==NULL)
89 {
90 cout<<"链表少于"<<num<<"个元素"<<endl;
91 return;
92 }
93 }
94 while(loop!=NULL)
95 {
96 loop=loop->link;
97 flag=flag->link;
98 }
99 cout<<"倒数第"<<num<<"个元素为："<<flag->data<<endl;
100 }
101
102
103 void findMidElement()
104 {
105 LinkNode<Type> *odd,*even;
106 odd=even=first;
107 while(even->link!=NULL)
108 {
109 odd=odd->link;
110 even=even->link;
111 if(even->link==NULL)
112 {
113 cout<<"中间元素是"<<odd->data<<endl;
114 return ;
115 }
116 even=even->link;
117 }
118 cout<<"中间元素是"<<odd->data<<"和"<<odd->link->data<<endl;
119 }
120
121
122 };
123
124
125 int main()
126 {
127 List<string> list;
128 list.inputRear("end");
129 list.output();
130 list.findReciprocalOfNum(5);
131 list.findReciprocalOfNum2(6);
132 list.findMidElement();
133 }