《C Primer Plus》,269页勘误,程序异常

269页程序清单10.19 flc.c程序有错误。

如图中所示,方法1处应加上const限定,否则有些编译器会出现从不兼容指针传递参数的警告,方法2没有方法1安全,方法2是去除原型和定义中的const限定。

图1
图2
下面展示第1种修改方法:
图3图4
像《c primer plus》这类厚书你花多长时间看完的? - 知乎
https://www.zhihu.com/question/420226549

protected void doPost HttpServletRequest request HttpServletResponse response throws ServletException IOException { String action request getParameter "action" ; Teacher t new Teacher ; t setUsername request getParameter "username" ; if "register" equals action { t setPassword MD5 generateMD5 request getParameter "password" ; if teacherDao add t >0 { request getSession setAttribute "mess" "恭喜 注册成功 " ; response sendRedirect "login jsp" ; }else{ response sendRedirect "error jsp" ; } }else if "login" equals action { t setPassword MD5 generateMD5 request getParameter "password" ; if teacherDao queryByTeacher t size >0 { Constants ONLINE COUNT++; Object oCount getServletContext getAttribute "count" ; if oCount null { getServletContext setAttribute "count" 1 ; }else{ getServletContext setAttribute "count" Integer getServletContext getAttribute "count" +1 ; } request getSession setAttribute "teacher" t ; request getSession setAttribute "students" studentDao queryStudentsByTeacher t ; if request getParameter "autoLogin" null { Cookie cookie1 new Cookie "username" t getUsername ; Cookie cookie2 new Cookie "password" t getPassword ; cookie1 setMaxAge 60 60 24 14 ; cookie2 setMaxAge 60 60 24 14 ; response addCookie cookie1 ; response addCookie cookie2 ; } response sendRedirect "index jsp" ; }else{ request setAttribute "mess" "用户名或密码错误 " ; request getRequestDispatcher "login jsp" forward request response ; } }else if "autoLogin" equals action { t setPassword request getParameter "password" ; if teacherDao queryByTeacher t size >0 { Constants ONLINE COUNT++; Object oCount getServletContext getAttribute "count" ; if oCount null { getServletContext setAttribute "count" 1 ; }else{ getServletContext setAttribute "count" Integer getServletContext getAttribute "count" +1 ; } request getSession setAttribute "teacher" t ; request getSession setAttribute "students" studentDao queryStudentsByTeacher t ; response sendRedirect "index jsp" ; }else{ request setAttribute "mess" "用户名或密码错误 " ; Cookie[] cookies request getCookies ; if cookies null { for Cookie cookie : cookies { if "username" equals cookie getName || "password" equals cookie getName { cookie setValue null ; 关键 cookie setMaxAge 0 ; response addCookie cookie ; } } } request getRequestDispatcher "login jsp" forward request response ; } }else if "loginOut" equals action { request getSession invalidate ; response sendRedirect "login jsp" ; } }">protected void doPost HttpServletRequest request HttpServletResponse response throws ServletException IOException { String action request getParameter "action" ; Teacher t new Teacher ; t setUsername request getParameter "username" ; if "register" equals ac [更多]
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