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我的一些理解。 面向过程,是对客观现象的描述,感觉是有一个上帝视角。 RedLightOn(); PeopleWalk(); CarStop(); GreenLightOn(); CarMove(); 面向对象,顾名思义,更加强调了客观实体与其属性和动作的关联性, 突出了以各个客观实体为中心的世界观, 可能更便于人类大脑理解与记忆。 redlight.turnOn(); people.walk(); car.stop(); greenlight.turnOn(); car.move();

Knapsack problem

The Knapsack Problem Let's apply what we're learned so far to a slightly more interesting problem. You are an art thief who has found a way to break into the impressionist wing at the Art Institute of Chicago. Obviously you can't take everything. In particular, you're constrained to take ...

opcode study

iconst_n Integers n = 0..5. the n indicates the const itself, not the index, and the const would be put into the stack. istore_n store integer in local variable n : n = 0..3 it says store integer. store what integer? actually it's the integer from the stack. iconst_< ...

2>&1&

a UNIX process has three standard file descriptors 0 == stdin 1 == stdout 2 == stderr the 2>&1 means attach fd 2 to write to the same as stream as fd 1, essentially calling dup2() the 2nd & means run the program in parallel, fork()/exec() but don't wait().     command >out.file ...

Big Collection

1. in regular item, soft code the zip code and store for dist level case 2. There’s nothing that says that complexity has to be a requirement for developing web applications. 3. CSS selectors represent an equally powerful concept, but are tuned for use within HTML pages, are a bit more concise, a ...
i finished it by fast reading as well as some sort of review of knowledge of this area, time could accumulate the essence and refine it through deep thinking.
如果一定要获得登录退出状态,就需要除了登录退出来确认在线下线外,还得有一个 在线确认+超时认定下线 机制 如果没有在线确认(比如心跳消息等),就无法确认是否没有主动退出,结合了超时认定下线就可以完善退出机制。 具体的可以查一下: 2、session何时被删除  综合前面的讨论,session在下列情况下被删除a.程序调用HttpSession.invalidate();或b.距离上一次收到客户端发送的session id时间间隔超过了session的超时设置;或c.服务器进程被停止(非持久session)http://beyond99.blog.51cto.com/1469451/54 ...

Spurious Wakup

http://www.devguli.com/blog/eng/spurious-wakeup/   en.wikipedia.org/wiki/Spurious_wakeup   虛假喚醒可能就是多核硬件環境下,JLS third爲了保證性能而作出的讓步。
Thursday, March 22, 2012   fiinished reading head first jquery   i feel i've got another much from this reading, just a memo.
$(document).ready(function(){ var FREQ = 10000 ; var repeat = true; function showFrequency(){ $("#freq").html( "Page refreshes every " + FREQ/1000 + " second(s)."); } function startAJAXcalls(){ if(repeat){ setTimeout( function() { ...

stack and heap

我觉得是根据应用方式 和本身特性 才将内存分区的,目的是提高效率 和方便管理 等 栈的特点是容量小,速度快,可能昂贵,就适合放置静态,全局等小且需要经常访问但不怎么变化的数据 堆的特点是容量大,速度慢,可能便宜,就适合放置动态分配的数据,因为动态分配的数据不确定且容量大,数量多,比如对象,生存期相对较短,就以无序状态存储于堆中。 像方法区之类是堆的一部分,我觉得更多是因为业务逻辑上便于分类管理的需要而应运而生的 详细可看:http://java.sun.com/docs/books/jvms/second_edition/html/Overview.doc.html htt ...
1. That seems like enough.   2. We often get the middle of an algorithm right but misjudge the boundaries.   3. They lose their trust in the original author and must fall back on reading the details of the code.   4. Turning off failing tests and telling yourself you’ll get them to pass later ...
How Selenium RC Works First, we will describe how the components of Selenium RC operate and the role each plays in running your test scripts. RC Components Selenium RC components are: The Selenium Server which launches and kills browsers, interprets and runs the Selenese commands passed from ...
For the server to run you’ll need Java installed and the PATH environment variable correctly configured to run it from the console. You can check that you have Java correctly installed by running the following on a console:   java -version   If you get a version number (which needs to be 1 ...

out there

i know out there out here for quite a long time, but never accquires its definite meaning. today i came upon it again, so i made a search. http://answers.yahoo.com/question/index?qid=20110213063113AAC19lC What's the meaning of "out there/here" in spoken English? I am an English l ...
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