Sometimes if you want to hide some important files on your computer which you don't want others to see, how would you do that? Find a professional tool? Set password for some folders? Change the file properties to hidden? They are possible, but they may not be so convenient or so secure. Here we share with you how to hide a file in a picture.Prerequisites1 picture for example : test.jpg1 test file, for example : test.txtWinRARStepsPrepare the picture test.jpg and test file test.txtUse WinRAR to compress test.txt to test.rarOpen command prompt : Start->Run->Type "cmd", then cd to the dire...

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 variable rather than read/write member variables directly.<?php    //dog_naive.php &...

In one of my current javascript projects, I have to deal with 3D voxel coordinates. And, sometimes, I have floating points coordinates which must be converted to integers in order to convert them into proper array index.Javascript is a wonderful language, really. However, implementations are sometimes weird, and the way to do something can sometimes have very huge impacts on the performances. Worse, sometimes the classical way is more expensive than the tricky one.So, some people have made performance comparisons on jsperf to check which is the fastest way to do. Most of these tests sa...

Preprocessor vs CompilerTo properly understand C macros, you must understand how a C program is compiled. In particular, you must understand the different things that happen in the preprocessor and in the compiler.The preprocessor runs first, as the name implies. It performs some simple textual manipulations, such as:Stripping comments. Resolving #include directives and replacing them with the contents of the included file. Evaluating #if and #ifdef directives. Evaluating #defines. Expading the macros found in the rest of the code according to those #defines.It is, of course, these...

1. Do not use relative paths , instead define a ROOT pathIts quite common to see such lines :1require_once('../../lib/some_class.php');This approach has many drawbacks :It first searches for directories specified in the include paths of php , then looks from the current directory.So many directories are checked.When a script is included by another script in a different directory , its base directory changes to that of the including script.Another issue , is that when a script is being run from cron , it may not have its parent directory as the working directory.So its a good idea to have absol...