相对于实验一，新增了2个类。
Class Listing vector.
Class Group vector.
使用到了向量。增强了大家对STL向量容器，以及实现所给的声明函数。
压缩包里面有代码，指导书，以及Apache服务器。-Prerequisites: Students should have mastered the following prerequisite skills.
C++ Class Specification- Produce C++ class implementations
Standard Template Library- Knowledge of the STL, particularly sequential containers and iterators
Goals: This assignment is designed to reinforce your understanding and use of the STL vector container and the Standard Template Library.
Outcomes: Students successfully completing this assignment would master the following outcomes.
Produce C++ class implementations given class declarations
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SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.089888s ]
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SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001250s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003686s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001105s ]
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SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.017483s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.002067s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 91802 [ RunTime:0.001631s ]
