本程序定义了一个wordstack类，可以储存字符串。

在pop字符串时候能够正确pop。



先将文件进行分析，对需要压入堆栈的字符串压入堆栈，然后进行判断。

可更改第20行中的test.txt为test2.txt和text3.txt测试其他结果-The program defines a wordstack class, you can store strings. In the pop strings when correctly pop. First file for analysis, the need for a string onto the stack onto the stack, and then judge. You can change the first 20 rows for test2.txt and text3.txt test test.txt other results