查找五：散列表查找

//散列表
#include<iostream>
using namespace std;
#define NULLKEY -32768
#define HASHSIZE 12 //定义散列表长度为12

struct HashTable
{
    int *elem;  //数据元素存储基址
    int count;  //当前数组元素个数
};

int m = 0; //散列表长度

//初始化散列表
bool InitHashTable(HashTable *H)
{
    m = HASHSIZE;
    H->count = m;
    H->elem = new int[m];
    for(int i=0;i<m;i++)
        H->elem[i] = NULLKEY;
    return true;
}

//散列函数
int Hash(int key)
{
    return key % m;
}

//插入关键字进散列表
void InsertHash(HashTable *H, int key)
{
    int addr = Hash(key);
    while(H->elem[addr] != NULLKEY)
    {
        addr = (addr+1)%m;
    }
    H->elem[addr] = key;
}

//散列表查找关键字
bool SearchHash(HashTable H, int key, int *addr)
{
    *addr = Hash(key);
    while(H.elem[*addr] != key)
    {
        *addr = (*addr+1)%m;
        if(H.elem[*addr]==NULLKEY || *addr == Hash(key))
            return false;
    }
    return true;
}

int main()
{
    int arr[HASHSIZE]={12,67,56,16,25,37,22,29,15,47,48,34};
    int i,p,key,result;
    HashTable H;

    key=39;

    InitHashTable(&H);
    for(i=0;i<m;i++)
         InsertHash(&H,arr[i]);
    
    result=SearchHash(H,key,&p);
    if (result)
        cout<<"查找 "<< key <<" 的地址为："<<p<<endl;
    else
        cout<<"查找 "<< key <<" 失败。"<<endl;

    for(i=0;i<m;i++)
    {
        key=arr[i];
        SearchHash(H,key,&p);
        cout<<"查找 "<< key <<" 的地址为："<<p<<endl;
    }

    return 0;
}