说明：  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 word, namely, the basic reserved words, identifiers, constants, Operators, separation top-five.)