数据结构知识的扩展，链表，二叉树，表达式求值的运用，用c++语言编写，在vc++6.0里面调试成功，可用于初学者或有基础的编程爱好者提高水平。-The expansion of knowledge of data structures, linked lists, binary trees, the use of expression evaluation, using c++ languages, debugging in vc++6.0 which success can be a basi