trie这种树也被称为线索，搜索树。

正如图

以下是用stl 的map来实现

class trie_item_c

{

public:

	trie_item_c(){}

	trie_item_c(const char nm)

	{

		name = nm;

	}

	void set_name(const char nm)

	{

		name = nm;

	}

	trie_item_c * get_child(const char nm)

	{

		map<const char ,trie_item_c*>::const_iterator it = children.find(nm);

		if(it != children.end())

			return it->second;

		else

		{

			trie_item_c *cld = new trie_item_c(nm);

			children.insert(pair <const char ,trie_item_c*>(nm,cld));

			return cld;

		}

	}

	bool find(const char* dic)

	{

		if(!dic || *dic == '\0')

		{

			if(children.end() != children.find('\0'))

				return true;

			return false;

		}

		const char* temp = dic;

		map<const char ,trie_item_c*>::const_iterator it = children.find(*temp);

		if(it == children.end())

			return false;

		return it->second->find(++temp);

	}

	void print()

	{

		printf("%c",name);

		map<const char ,trie_item_c*>::const_iterator it = children.begin();

		for(;it != children.end();it++)

		{

			it->second->print();

		}

		printf("\n");

	}

	virtual ~trie_item_c()

	{

		map<const char ,trie_item_c*>::const_iterator it = children.begin();

		while(it != children.end())

		{

			delete it->second;

			children.erase(it);

			it = children.begin();

		}

	}

private:

	map<const char ,trie_item_c*> children;

	char name;

};

以下代码是构建树的过程

for(const char* dic = lst.first_string();dic;dic = lst.next_string())

	{

		trie_item_c *temp = root;

		for(int i=0;i<str_temp.str_len();i++)

		{

			char c = str_temp.get(i);

			trie_item_c *item = temp->get_child(c);

			temp = item;

		}

		//add one null child

		temp->get_child('\0');

	}

推断是否一个字root在，只需要调用root->find("book");您可以。