三种hash函数实现数据的散列

通过三种hash函数将数据散列到对应的键值当中，而对于有冲突的键用链表储存数据。在这里只是用链表保存了与字符串首字母对应的指针，散列表的大小一般选择素数。参考书目《数据结构与算法分析》

//接口函数

#ifndef _HASH_H
#define _HASH_H
struct listnode
{
	char *str;
	struct listnode *Next;
};
typedef struct listnode ListNode;
typedef ListNode *Position;
struct HashTab
{
	int TableSize;
	Position *TheLists;
};
typedef struct HashTab *HashTable;
HashTable InitTable(int TableSize);
void DestroyTable(HashTable H);
Position Find(char *str,HashTable H);
void Insert(char *str,HashTable H);
void VisitAllList(HashTable H);
#endif

//接口函数定义

#include 
#include 
#include 
#include "hash.h"
#define MinTableSize 2
typedef int Index;
Index Hash(const char *Key,int TableSize)//三种hash函数映射
{
	unsigned int HashVal=0;
	while(*Key!=0)
		HashVal=(HashVal<<5)+*(Key++);
	return HashVal%TableSize;
}
/*Index Hash(const char *Key,int TableSize)
{
	unsigned int HashVal=0;
	while(*Key!='\0')
		HashVal+=*Key++;
	return HashVal%TableSize;
}*/
/*Index Hash(const char *Key,int TableSize)
{
	return (Key[0]+27*Key[1]+729*Key[2])%TableSize;
}*/
HashTable InitTable(int TabSize)
{
	HashTable H;
	int i;
	if(TabSizeTableSize=TabSize;
	H->TheLists=(ListNode **)malloc(sizeof(ListNode *)*H->TableSize);
	if(H->TheLists==NULL)
		printf("Out of space!!");
	for(i=0;iTableSize;i++)
	{
		H->TheLists[i]=NULL;
	}
	return H;
}
Position Find(char *Key,HashTable H) 
{
	Position P;
	P=H->TheLists[Hash(Key,H->TableSize)];
	while(P!=NULL&&(strcmp(Key,P->str)!=0))
		P=P->Next;
	return P;
}
void Insert(char *Key,HashTable H) //映射到各个键值当中
{
	Position NewCell,Pos;
	int mod;
	Pos=Find(Key,H);
	if(Pos==NULL)
	{
		NewCell=(ListNode *)malloc(sizeof(ListNode));
		if(!NewCell)
			printf("Out of space");
		else
		{
			mod=Hash(Key,H->TableSize); //链表储存(类似于栈储存)
			NewCell->Next=H->TheLists[mod];
			NewCell->str=Key;
			H->TheLists[mod]=NewCell;
		}
	}
}
void VisitAllList(HashTable H)
{
	int i;
	Position P;
	for(i=0;iTableSize;i++)
	{
		P=H->TheLists[i];
		while(P!=NULL)
		{
			printf("%s ",P->str);
			P=P->Next;
		}
		printf("\n");
	}
}
void DestroyTable(HashTable H)
{
	int i;
	Position current,temp;
	for(i=0;iTableSize;i++)
	{
		current=H->TheLists[i];
		while(current!=NULL)
		{
			temp=current->Next;
			free(current);
			current=temp;
		}
	}
	free(H->TheLists);
	free(H);
}

//main函数入口

#include 
#include "hash.h"
int main(int argc, char **argv)
{
	int TabSize,i;
	//char *buf="kindle";
	char *buf[17]={"kiss","print","java","kugou","follow","scanf","rather","python","kidney","heaven",

"china","English","tell","again","begin","dance","write"};
	HashTable H;
	printf("Please enter the size of Hash Table:\n");
	scanf("%d",&TabSize);
	H=InitTable(TabSize);
	for(i=0;i<17;i++)
	{
		Insert(buf[i],H);
	}
	VisitAllList(H);
	DestroyTable(H);
	return 0;
}

//测试结果

hash函数1

hash函数2

hash函数3

由于散列键值和散列元素选择较少无法体现三个hash函数的散列效果