哈希表实现

 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 
 //定义hash表结构
 typedef struct _node{
     char *name;
     char *desc;
     struct _node *next;
 }node;
 
 //hash表大小
 #define HASHSIZE 101
 static node* hashtab[HASHSIZE];
 
 //初始化hash表
 void inithashtab(){
     int i;
     for(i=0;i<HASHSIZE;i++)
         hashtab[i]=NULL;
 }
 
 //解决冲突函数
 unsigned int hash(char *s){
     unsigned int h=0;
     for(;*s;s++)
         h=*s+h*31;
     return h%HASHSIZE;

 }
 
 //根据健获取集合节点
 node* lookup(char *n){
     unsigned int hi=hash(n);
     node* np=hashtab[hi];
     for(;np!=NULL;np=np->next){
         if(!strcmp(np->name,n))
             return np;
     }
     
     return NULL;
 }
 
 char* m_strdup(char *o){
     int l=strlen(o)+1;
     char *ns=(char*)malloc(l*sizeof(char));
     strcpy(ns,o);
     if(ns==NULL)
         return NULL;
     else
         return ns;
 }
 //根据健获取值
 char* get(char* name){
     node* n=lookup(name);
     if(n==NULL)
         return NULL;
     else
         return n->desc;