const int MaxKeySize = 25;		typedef enum { branch, element } NODETYPE;		        class KeyType		{ 						//關(guān)鍵碼的類型定義		public:		   char ch[MaxKeySize];					//存放關(guān)鍵碼的字符數(shù)組		   int currentSize;						//關(guān)鍵碼的長(zhǎng)度		   int operator == (const KeyType &);		} ;				template <class RecordNode> class Trie;		template <class RecordNode>		class TrieNode {						//Trie樹(shù)結(jié)點(diǎn)的類定義		friend class Trie<RecordNode>;						//友元類		protected:		   NODETYPE NodeType;			//結(jié)點(diǎn)分類		   union NodeType {					//結(jié)點(diǎn)結(jié)構(gòu)定義			 struct {						//分支結(jié)點(diǎn)			   int num;						//在分支結(jié)點(diǎn)中非空指針個(gè)數(shù)			   TrieNode *link[27];				//下標(biāo)為'b', 'a', 'b', …, 'z'的指針數(shù)組			 } brch;			 struct {						//元素結(jié)點(diǎn)			   KeyType key;					//關(guān)鍵碼			   RecordNode *recptr;				//指向?qū)嶋H數(shù)據(jù)記錄的指針			 } elem;		   }data;		};		template <class RecordNode>		class Trie {							//Trie樹(shù)的類定義		private:		   TrieNode<RecordNode> *root, *current;				//Trie的根指針和當(dāng)前指針		public:		   RecordNode* Search ( const KeyType & );		   int Insert ( const KeyType & ); 		   int Delete ( const KeyType & );		};		template <class RecordNode>			RecordNode* Trie<RecordNode>::Search ( const KeyType & x ) {		//在一棵Trie樹(shù)上搜索關(guān)鍵碼x。設(shè)第i-1層的分支是由關(guān)鍵碼的第i個(gè)字符決定的。		   KeyType k = x;  		   concatenate ( k, 'b' );				//在搜索值后面連接一個(gè)結(jié)束符'b'		   current = root;  		   int i = 0;					//從根開(kāi)始，先在結(jié)點(diǎn)中判斷		   while ( (current) && (current->NodeType != element) && (i <= k.ch[i]) )			 { current = current->data.brch.link[k.ch[i]];  i = i++; };			  //從根向下逐層比較, ord (k.ch[i])是字符k.ch[i]在字母表中的序號(hào), 'b'是第0個(gè)		   if ( (current) && current->NodeType == element && current->data.elem.key == x )			 return current->data.elem.recptr;				//找到, 返回對(duì)應(yīng)記錄位置	 		 else return 0;						//沒(méi)有找到, 返回空地址		}		int KeyType:: operator == (const KeyType & d)		{			if (currentSize!=d.currentSize) return 0;			for (int i=0;i<currentSize;i++)				if (ch[i]!=d.ch[i]) return 0;			return 1;		};