哈希表C++实现--hash_table

#include <iostream>
3 #include <string>
4 #include <string.h>
5 #include <vector>
6 #include <stdio.h>
7 using namespace std;
8
9 struct table_node
10 {
11     int _key;
12     string _value;
13     struct table_node *next;
14     table_node(const int key,const string &value)
15         :_key(key),_value(value),next(NULL)
16     {}
17 };
18
19
20 class hash_table
21 {
22     private:
23         vector<table_node*> vector_node;
24         size_t size;
25     private:
26         size_t fun_index(const int key)
27         {
28             return key % vector_node.size();
29         }
30         size_t get_size()
31         {
32             const int len=10;
33             static size_t arr[len]={53,97,193,389,769,1543,3079,6151,12289,24593};
34             static int i=0;
35             return arr[i++];
36         }
37         void init_hash_table()
38         {
39             if(vector_node.size()==size)
40             {
41                 vector<table_node*> new_node;
42                 size_t new_size=get_size();
43                 new_node.resize(new_size);
44                 //////////
45                 //再把之前vector的数组拷贝到新的vector中
46                 for(int i=0; i<vector_node.size(); ++i)
47                 {
48                     table_node *cur=vector_node[i];
49
50                     while(cur !=NULL)
51                     {
52                         size_t index=fun_index(cur->_key);
53                         table_node *tmp=cur;
54                         cur=cur->next;
55
56                         table_node *value=new_node[index];
57                         if(value==NULL)
58                             new_node[index]=tmp;
59                         else
60                         {
61                             tmp->next=value->next;
62                             value->next=tmp;
63                         }
64                     }
65                 }
66                 vector_node.swap(new_node);
67             }
68         }
69     public:
70         hash_table(size_t sz=0):size(sz)
71         {}
72         void insert(const int key,const string &value)
73         {
74             init_hash_table();
75
76             table_node *tmp=new table_node(key,value);
77
78             size_t index=fun_index(key);
79             table_node *cur=vector_node[index];
80
81             if(cur==NULL)
82                 vector_node[index]=tmp;
83             else if(cur !=NULL)
84             {
85                 tmp->next=cur->next;
86                 cur->next=tmp;
87             }
88             size++;//在这让size++的目的是为了让负载因子为一，即一个下表下只挂一个数据
89         }
90         void show()
91         {
92             for(int i=0; i<vector_node.size(); ++i)
93             {
94                 cout<<"第"<<i+1<<"个：";
95                 table_node *cur=vector_node[i];
96                 while(cur !=NULL)
97                 {
98                     cout<<cur->_value<<"-->";
99                     cur=cur->next;
100                 }
101                 cout<<" NULL"<<endl;
102             }
103         }
104         void remove(const int &key)
105         {
106             size_t index=fun_index(key);
107             table_node *cur=vector_node[index];
108             if(cur !=NULL)
109             {
110                 if(cur->next==NULL)
111                 {
112                     delete vector_node[index];
113                     vector_node[index]=NULL;
114                 }
115                 else
116                 {
117                     table_node *tmp=cur->next;
118                     cur->next=tmp->next;
119                     delete tmp;
120                 }
121             }
122         }
123 };

#include "hash_table.h"
3
4 void fun_hash_table()
5 {
6     hash_table t;
7     t.insert(2,"1-hello");
8     t.insert(2,"2-hello");
9     t.insert(2,"3-hello");
10     t.insert(2,"4-hello");
11     t.insert(3,"world");
12     t.insert(4,"Hello");
13     t.insert(5,"hello");
14     t.show();
15 }
16 int main()
17 {
18     fun_hash_table();
19     return 0;
20 }
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