c—语言的句法分析器。读入一个C--语言程序，判断该程序是不是一个合法的C--语言程序。如果程序有语法和语义错误，则给出错误信息。-c-language parser. Read into a C- language program, to determine whether the program is not a valid C- language program. If the program has syntax and semantic errors, then gives an error message.