基于链地址法的散列表查找

#include<iostream>
using namespace std;
typedef int keyType;
typedef struct HashTable {
  keyType key;
  struct HashTable * next;
}HashTable, *HashTree;

class Hash {
public:
  int curTable;//当前
  //定义哈希函数
  HashTree hashTable;
  int maxTable;//表长
  Hash(int length) {
    curTable = 0;
    maxTable = length;
    hashTable = new HashTable[length];
    for (int i = 0; i < length; i++)//初始化数值全为-1表示单元为空
    {
      hashTable[i].key = -1;
      hashTable[i].next = NULL;
    }
  }
  ~Hash() {
    delete[]hashTable;
    hashTable = NULL;
  }
  int H(int key) {
    return key % 7;
  }
  bool Insert(keyType &  key) {
    int ant = H(key);
    HashTable *  p = & hashTable[ant];
    hashTable[ant].key = ant;
    while ( p->next) {
      if ( p-> next->key ==key) {
        return false;
      }
      p = p->next;
    }//while

    HashTable *s = new HashTable;
    s->key = key;
    s->next = NULL;

    p->next = s;
    return true;
  }
  bool Delete(keyType & key) {
    int ant = H(key);
    HashTable *  p = &hashTable[ant];
    HashTable *  s;
    while (p->next) {
      if (p->next->key == key) {
        s = p->next;
        p->next = s->next;
        delete s;
        s = NULL;
        return true;
      }
      p = p->next;
    }//while
    return false;
  }

  void display()
  {
    for (int i = 0; i < maxTable; i++)
    {
      cout << i;
      HashTable *  s;
      if (hashTable[i].key != -1) {
        s = hashTable[i].next;
        while (s != NULL) {
          cout << "---->" << s->key;
          s = s->next;
        }
      }
      cout << endl;
    }
  }
  //###重点：散列表的查找###//
  int searchHash( keyType data) {
    //如果成功，则放回单元标号，否则返回-1
    int H0 = 0;
    H0 = H(data);
    if (hashTable[H0].key == -1) return -1;//没有存在
    else if (hashTable[H0].key == H0) {
      HashTable *  s= hashTable[H0].next;
      while (s != NULL) {
        if (s->key == data) {
          return H0;
        }
        s = s->next;
      }
      return -1;  
    }
  }

};

int main() {
  //针对课本课后习题
  /*
  对9,1,23,14,55,20,84,27，采用散列函数H(KEY)=KEY%7,表长度为10,链地址法的实现
  */
  int a[] = { 9,1,23,14,55,20,84,27 };
  int n = sizeof(a) / sizeof(a[0]);
  cout << "n=" << n << endl;
  Hash h(10);
  for (int i = 0; i < n; i++)
    h.Insert(a[i]);
  h.display();
  //delete
  cout << "Please input the number you wanna delete" << endl;
  keyType data;
  while (cin>>data) {
    if (data >= 0) {
      if (h.Delete(data)) {
        h.display();
      }
      else
        cout << "不存在" << endl;
      cout << "Please input the number you wanna delete" << endl;
    }else 
      cout << "Please input the number you wanna delete" << endl;
  }
  //~delete
  //locate
  cout << "Please input the number you wanna locate" << endl;
   while (  scanf_s("%d",&data)!=EOF  ) {
    if (data >= 0) {
      if (h.searchHash( data) == -1) {
        cout << "不存在" << endl;
      }
      else
        cout << data<< " locates at hashTable[" << h.searchHash( data) <<"]"<< endl;
      cout << "Please input the number you wanna locate" << endl;
    }
    else
      cout << "Please input the number you wanna locate" << endl;
  }
  //~locate
  return 0;
}