好久没看数据结构了，今天终于要用到hash，整理一下写了个hash类模板

template<typename T>class DataType
{
public: T key;DataType(T k):key(k){}DataType(void){}bool operator ==(const DataType &a){return key == a.key;}bool operator !=(const DataType &a){return key != a.key;}};enum KindOfItem{Empty, Active, Delete};template<typename T>
class HashItem
{
public:DataType<T> data;KindOfItem info;HashItem(KindOfItem i = Empty):info(i){}HashItem(DataType<T> d, KindOfItem i = Empty):data(d),info(i){}bool operator ==(const HashItem & a){return a.data == data;}bool operator !=(const HashItem &a){return a.data != data;}};template<typename T>
class HashTable
{
public:const int size;HashItem<T> *ht;int FindItem(const HashItem<T> &a);int InsertItem(const HashItem<T> &a);int DeleteItem(const HashItem<T> &a);HashTable(int k);~HashTable();};

template<typename T>
HashTable<T>::HashTable(int k):size(k),ht(0)
{ht = new HashItem<T>[size];
}template<typename T>
HashTable<T>::~HashTable()
{if (ht){delete[]ht;ht =0;}
}template<typename T>
int HashTable<T>::FindItem(const HashItem<T> &a)
{int i = a.data.key%size;int j = i;while (ht[j].info == Active && ht[j].data != a.data){j = (j+1)%size;if (j == i){return -size;}}if (ht[j].info == Active){cout<<"发现数据"<<endl;return j;}else{return -j;}return 0;
}template<typename T>
int HashTable<T>::InsertItem(const HashItem<T> &a)
{int i = FindItem(a);if (i > 0 || (i==0 && ht[0].info == Active)){return -1;}if (i == -size){cout<<"hashtable已满，插入失败"<<endl;return -1;}else{ht[-i] = a;ht[-i].info = Active;}cout<<"插入成功"<<endl;return i;}template<typename T>
int HashTable<T>::DeleteItem(const HashItem<T> &a)
{int i = FindItem(a);cout<<i<<endl;if (i < 0|| (i==0 && ht[0].info != Active)){cout<<"无此数据"<<endl;return -1;}ht[i].info = Delete;cout<<"删除成功"<<endl;return i;}