哈希函数示例

#include "stdafx.h"
#include <malloc.h>
#include <stdio.h>
#include <iostream>
using namespace std;

typedef int keytype;

typedef struct chain
{
    keytype key;
    chain* next;
}chaintype;

int HashInsert1(chaintype *a[],keytype key,int (*Hash)(keytype,int),int mod);
chaintype* HashSearch1(chaintype* a[],keytype key,int (*Hash)(keytype,int),int mod);
int Hash1(keytype key,int mod);

int _tmain(int argc, _TCHAR* argv[])
{
    int i,key,mod=10;
    int Test[10]={1,2,3,4,5,6,66,666,7,11};
    chaintype* a[10],*p;
    int( *Hash)(keytype,int);
    
    //初始化哈希表
    for(int i=0;i<10;i++)
    {
       a[i]=NULL;
    }
    
    Hash=Hash1;
    //建立哈希表
    for(int i=0;i<10;i++)
    {
       HashInsert1(a,Test[i],Hash,mod);
    }
    
    //查找Key为666的记录
    key=8;
    p=HashSearch1(a,key,Hash,mod);
    if(p!=NULL) printf("\n查找成功！");
    else printf("\n查找失败！");
    
    int c;
    cin>>c;
    return 0;
}

//哈希查找函数
chaintype* HashSearch1(chaintype* a[],keytype key,int (*Hash)(keytype,int),int mod)
{
    int i=Hash(key,mod);
    chaintype* cur=a[i];
    
    while(cur!=NULL && cur->key!=key)
    {
        cur=cur->next;
    }
        
    if(cur==NULL) return NULL;
    else return cur;
}

//用链式地址法解决哈希冲突
int HashInsert1(chaintype *a[],keytype key,int (*Hash)(keytype,int),int mod)
{
    int i=Hash(key,mod);
    chaintype *pre,*cur;   
    cur=a[i];
    
    while(cur!=NULL && cur->key!=key)
    {
        pre=cur;
        cur=cur->next;        
    }
    
    if(cur==NULL)
    {
        cur=(chaintype*)malloc(sizeof(chaintype));
        cur->key=key;
        cur->next=NULL;          
        
        if(a[i]==NULL) 
        {
            a[i]=cur;
        }
        else
        {
            pre->next=cur;
        }      
        
        return 1;
    }
   
    
    return 0;
}


//除模取余的哈希函数
int Hash1(keytype key,int mod)
{
    return key%mod;
}