此课设是if else 条件语句的翻译程序.

功能说明如下：

1.整体词法分析；

2.if else语法分析，递归下降法.

3.三地址形式代码格式输出；

4.变量符号表的实现，即先定义变量才可以使用；

5.出错提示，具体行数出错提示；

6.作用域初步设计.-This lesson is that if else conditional statements of the translation process. Functions as follows: 1. The overall lexical analysis　2.if else parsing, recursive descent method. 3. Third, address the form of output code format　4. The realization of the variable symbol table , that is, the definition of variables can be used　5. error prompts, error prompts specific number of rows　6. the scope of the preliminary design.