毛坯表达式 求值器，用bison写的。麻雀虽小，五脏俱全的，主要的特征都用到了，gcc的语法分析也不过就用了这些方法。 -blank expression evaluator with bison writes. This small, perfectly formed, the main features are used, gcc syntax analysis However, on the use of these methods.

表达式的求值~~~~~输入任意个表达式,都能求出他的值~

此源码是用C写的，用于一般表达式的求值。由于是用C写的，可以跨平台使用。你也可以取其中的功能函数嵌入到其他项目中作为一个功能组件。-This source code is written in C, for the general expression to be evaluated. Because it is written in C, can be cross-platform use. You can also take one of the feature functions embe