HashTable类模板_C++

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;

}