DS二叉树--叶子数量

#include <iostream>
#include <string>
using namespace std;
class BiTreeNode {
public:
	char  data;					//数据域
	BiTreeNode  *leftChild,  *rightChild;	//左右子树指针
	BiTreeNode():leftChild(NULL), rightChild(NULL){}
	~BiTreeNode() {}
};

class BiTree {
private:
	BiTreeNode *root;	//根结点指针
	string sTree;		//建树字符串
	int pos;			//标识建树字符串的当前字符位置
	BiTreeNode * CreateTree();//建树私有函数
    int leave=0;
public:
	BiTree():root(NULL) {};
	void Create(string vArray);	//建树公有接口，参数是特定的先序遍历字符串
    void CountLeave(BiTreeNode*T) {
        if(T==NULL)
            return;
        CountLeave(T->leftChild);
        CountLeave(T->rightChild);
        if(T->rightChild==NULL&&T->leftChild==NULL)
            leave++;
    }
    void ShowLeave(){
        CountLeave(root);
        cout<<leave<<endl;
    }
};
void BiTree::Create(string vArray)
{	pos=0;
	sTree.assign(vArray);	//把参数保存到内部字符串
	root = CreateTree();	//建树成功后root指向根结点
}
BiTreeNode* BiTree::CreateTree() {
    if(pos==sTree.size()||sTree[pos]=='0'){
        pos++;
        return NULL;
    }

    BiTreeNode*T=new BiTreeNode();
    T->data=sTree[pos++];
    T->leftChild=CreateTree();
    T->rightChild=CreateTree();
    return T;
}
int main()
{	int t;
	string vArray;
	cin>>t;
	while(t--)
	{	cin>>vArray;
		BiTree myTree;
		myTree.Create(vArray);
		myTree.ShowLeave();
	}
	return 0;
}