SEARCH KEYWORD -- Code Jam 2013

  Obviously Correct

What do automatic memory management, static types and purity have in common? They are methods which take advantage of the fact that we can make programs obviously correct (for some partial definition of correctness) upon visual inspection. Code using automatic memory management is obviously correct for a class of memory bugs. Code using static types is obviously correct for a class of type bugs. Code using purity (no mutable references or side effects) isobviously c...

   Memory management,Code,Static,Purity     2011-11-07 08:13:05

  The trap of the performance sweet spot

This post is about JavaScript performance but I would like to start it by telling a story that might seem unrelated to JS. Please bear with me if you don’t like C.A story of a C programmer writing JavaScriptMr. C. is a C programmer as you can probably guess from his name. Today he was asked by his boss to write a very simple function: given an array of numbered 2d points calculate vector sum of all even numbered points... He opens his favorite text editor and quickly types somet...

   C,JavaScript,Sweet spot,Memory,Low level,Trap     2011-11-06 14:45:01

  Efficiency of code execution

If you want to optimize your program codes, you need to find their Hotspot, i.e, the codes which are executed most frequently. If you can optimize this portion of codes a bit, you may gain much improvement of your code efficiency. Here I give you three examples about efficiency of code execution.1. PHP's Getter and Setter (From Reddit)This example a quite simple, you can skip it if you want.Consider the code below, we can find it's slower when we use Getter/Setter method to read a member variabl...

   Code, Efficiency,Analysis,Trick     2012-07-13 10:59:21

  Permutation algorithm with JavaScript

In secondary school, we have learned permutation. Basically, for n numbers, the number of permutations for these n numbers can be calculated to n! which is called 'n factorial'. But to display all the permutations on the screen, we need to use a recursive function. The problem is how to write this function.  Next I write a program to display the permutations for n numbers with JavaScript. First, we need to understand that from these n numbers, we can first take any one number from it, and t...

   JavaScript,Permutation,Algorithm,Impleme     2011-09-21 12:02:35

  10 Reasons Why Visual Basic is Better Than C#

Visual Basic is a better programming language than Visual C#. Who says so? This article! Here are 10 reasons why you should always choose VB over C#. 1 – “Rose is a rose is a rose is a rose” This is a quotation from Gertrude Stein’s 1922 play Geography and Plays. However, the poetry wouldn’t work in C#, because – unforgivably – it’s a cASe-SeNSitIvE language. This is madness! Before I start ranting, let me just acknowledge that case-sens...

   Visual basci,C#,Advantage,Comparison     2012-03-10 04:24:03

  Create Packed Indexes with MySQL

I am pretty much sure that you are aware of indexes which we are creating on database fields. Indexes are very useful to make your query search faster and improve the site performance. But the fact is that Indexes which we are creating on database tables also require some additional space on your hard disk and if you have not properly created these indexes than some t...

   MySQL,Compressed index,PACK_KEYS     2012-04-24 07:42:18

  SSH Security and You - /bin/false is *not* security

Backstory While at RIT around 2004 or 2005, I discovered that a few important machines at the datacenter allowed all students, faculty, and staff to authenticate against them via ssh. Everyone's shells appear to be set to /bin/false (or some derivative) on said machines, so the only thing you'll see after you authenticate is the login banner and your connection will close. I thought to myself, "Fine, no shell for me. I wonder if port forwarding works?" ...

   Linux,Security,/bin/false,SSH     2012-02-06 07:46:29

  Kicking ass together: How to improve coding skills as a group

Over the last year and a half, I have worked with a small group of students and staff to create an excellent online learning community at Mendicant University. Unfortunately, because Mendicant is something that we’re intentionally scaling at a very slow pace, we won’t directly reach as many people as we’d like to any time soon. In this post, I’ve collected some of the things that I think contribute to making Mendicant University a great place to learn. I’d love...

   Code skill,Group,Improvement,Efficiency     2012-01-31 23:59:33

  A JS1K competition demo for 2012

JS1K is a website which hosts some competitions to attract geeks from the world to create  JS apps which are less than 1K (1024 bytes). The object of this competition is to create a cool JavaScript "application" no larger than 1k. Starting out as a joke, the first version ended with a serious amount of submissions, prizes and quality.Recently, I revised a previous project of mine and compressed it to 1018 bytes and submitted it. It is an analog clock. The code is shown below:w=c.width;h=c...

   JS1K,HTML5,Competition,Analog clock,Love     2012-03-13 12:17:40

  Three ways to define class in JavaScript

In object oriented programming, class is the template of object, it defines the properties and methods of a group of objects. Unfortunately, JavaScript doesn't support class, but we can have some workarounds to simulate class.1. Constructor functionThis is the classical approach, it is also the approach mentioned in many text books. It uses the constructor function to simulate class and it uses the keyword this to represent the object internally.function Cat() {　　this.name = "Kelly...

   JavaScript,Class,Method,Private,Inheritance     2012-07-09 11:59:51

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