用于叶子结点的遍历
int main()
{
BiTree T;
InitBiTree(T);
cout<<"请按前序遍历输入各结点的数据\n";
CreateBiTree(T);
cout<<"前序遍历\n";
PreOrderTraverse(T);
cout<<endl;
cout<<"中序遍历\n";
InOrderTraverse(T);
cout<<endl;
cout<<"后序遍历\n";
PostOrderTraverse(T);
cout<<endl;
cout<<"层次遍历\n";
LevelTraverse(T);
cout<<endl;
cout<<"叶子结点数为:";
cout<<LeaveNum(T);
return 0;
}