通过设计编制调试一个具体的词法分析程序，加深对词法分析原理的理解。并掌握在对程序设计语言源程序进行扫描过程中将其分解为各类单词的词法分析方法。

编制一个读单词过程，从输入的源程序中，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。并依次输出各个单词的内部编码及单词符号自身值。

-Design prepared by commissioning a specific lexical analysis program to deepen the understanding of the principles of lexical analysis. And mastery of the programming language source code scanning process will be broken down into various types of word lexical analysis methods.

The preparation of a read word process, from input source to identify the independent significance of each word, which basically reserved words, identifiers, constants, operators, delimiters five categories. And in turn the output of each word its own internal code word symbols and values​ ​ .