哈希表存人名。。= =

详见 清华大学出版社的《数据结构题集（C语言版）》   P166 6.2

哈希表采用数组形式实现,方便操作.

构造哈希表时对冲突的处理采用为随即再散列法,虽然这很容易实现,但是在插入和查找时得分开进行处理,否则会导致正确的hash被跳过去,只能生成未被占用的hash,导致查找的时候始终无法找到关键字.因此在CreateHash函数中加入了判断条件,除了比对该hash有没有被占用之外还要比对占用的关键字是否与生成hash的关键字相同.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct HashNode
{
    char name[30];
    int flag;
}HashNode;

HashNode HashTable[60];

void InsertHash(long int hash, char *name)
{
    strcpy(HashTable[hash].name, name);
    HashTable[hash].flag = 1;
}

int SearchHash(long int hash)
{
    if (HashTable[hash].flag == 1)
        return 1;
    else
        return 0;
}

long int CreateHash(char *name)
{
    int i, n;
    long int hash = 0;
    n = strlen(name);
    for (i = 0; i < n; i++)
    {
        hash += name[i];
    }
    hash = hash % 60;
    
    while (SearchHash(hash) == 1 && strcmp(HashTable[hash].name, name) != 0)
        hash = (hash + abs(rand())) % 60;
    return hash;
}

void InitHashTable()
{
    int i;
    for (i = 0; i < 60; i++)
        HashTable[i].flag = 0;
}

void main()
{
    int temp;
    char input[30] = "Initial";
    InitHashTable();
    printf("Input names below,end up inputting with \"E\"\n");
    do
    {
        if (strlen(input) != 1)
        {
            scanf("%s", input);
            getchar();
            InsertHash(CreateHash(input), input);
        }
    }
    while (strlen(input) != 1);
    printf("\nSearch:");
    scanf("%s", input);
    do
    {
        temp = CreateHash(input);
        if (SearchHash(temp) == 1 && strcmp(HashTable[temp].name, input) == 0)
        {
            printf("\nFound.\n");
            getchar();
            scanf("%d");
            return;
        }
    }
    while (SearchHash(temp) == 1);
    printf("\nNot Found.\n");
    getchar();
    scanf("%s", input);
}