编写求二叉树的叶子结点数的函数模板。

[算法]

求一棵二叉树的叶子结点数的递归模型如下。

f(btree)=0 若为空树时

f(btree)=1 　　　　　　　　　　若只有根结点时,该根结点是叶结点-Leaves the preparation of the binary tree nodes seek the function template. [Method] request a binary tree leaf nodes of the recursive model is as follows. f (btree) = 0　if empty tree f (btree) = 1　if only the root, the root is a leaf node