C++面向对象程序设计-桌面计算器实现

C++面向对象程序设计-桌面计算器实现

源代码

/** 
*****************
* program:
*     END                  //END is end-of-input
*     expr_list END
* expr_list:
*     expression PRINT     // PRINT is semicolon
*     expression PRINT expr_list
* expression:
*     expression + term
*     expression - term
*     term
* term:
*     term / primary
*     term * primary
*     primary
* primary:
*     NUMBER
*     NAME    				// this is variable
*     NAME = expression
*     - primary
*     ( expression )
*/
#include
#include
#include