由VC++构建的词法分析器,实现简单的词法分析器，从输入的测试程序中，识别出各个具有独立意义的单词，即基本保留字、标识符、常数、运算符、分隔符五大类。-VC constructed by the lexical analyzer and achieve simple lexical analyzer, from the import of testing procedures, all identified with the independent significance of the wor