字典树实现代码

求优化 

#include<iostream>
#include<string.h>

using namespace std;

#ifndef _Trie_
#define _Trie_
struct Trie_Node
{
    bool isStr;
    Trie_Node * next [26];
    Trie_Node(void):isStr(false){memset(next,0,sizeof(next));}
};
typedef Trie_Node * Trie_Position;

void insert(Trie_Position root,char val[]);
void remove(Trie_Position root,char val[]);
bool isHere(Trie_Position root,char val[]);
#endif

int main()
{
    Trie_Position root = new Trie_Node;
    return 0;
}

void insert(Trie_Position root,char val[])
{
    Trie_Position position = root;
    for(int i=0,l=strlen(val),key;key=val[i]-'a',l-i>0;i++)
    {
        if(!position->next[key]) position->next[key]=new Trie_Node;
        position=position->next[key];
    }
    position->isStr=true;
}
void remove(Trie_Position root,char val[])
{
    Trie_Position position = root;
    for(int i=0,l=strlen(val),key;key=val[i]-'a',l-i>0;i++)
    {
        if(!position->next[key]) return;
        position=position->next[key];
    }
    position->isStr=false;
}
bool isHere(Trie_Position root,char val[])
{
    Trie_Position position = root;
    for(int i=0,l=strlen(val),key;key=val[i]-'a',l-i>0;i++)
    {
        if(!position->next[key]) return false;
        position=position->next[key];
    }
    return position->isStr;
}