Tutorial by Examples: l

In languages such as C, the @goto statement is often used to ensure a function cleans up necessary resources, even in the event of an error. This is less important in Julia, because exceptions and try-finally blocks are often used instead. However, it is possible for Julia code to interface with C ...

If you implement or create a listener in an Activity, always pay attention to the lifecycle of the object that has the listener registered. Consider an application where we have several different activities/fragments interested in when a user is logged in or out. One way of doing this would be to h...

% set mypath /home/tcluser/sources/tcl/myproject/test.tcl /home/tcluser/sources/tcl/myproject/test.tcl % set dir [file dirname $mypath] /home/tcluser/sources/tcl/myproject % set filename [file tail $mypath] test.tcl % set basefilename [file rootname $filename] test % set extension [file exte...

Consider the following code snippet: // Print the sum of the numbers 1 to 10 int count = 0; for (int i = 1; i < 010; i++) { // Mistake here .... count = count + i; } System.out.println("The sum of 1 to 10 is " + count); A Java beginner might be surprised to know that the...

The javadoc for the Thread class shows two ways to define and use a thread: Using a custom thread class: class PrimeThread extends Thread { long minPrime; PrimeThread(long minPrime) { this.minPrime = minPrime; } public void run() { // compute primes l...

Jumping out of nested loops would usually require use of a boolean variable with a check for this variable in the loops. Supposing we are iterating over i and j, it could look like this size_t i,j; for (i = 0; i < myValue && !breakout_condition; ++i) { for (j = 0; j < mySecondVa...

A lot of people who are new to multi-threading think that using threads automatically make an application go faster. In fact, it is a lot more complicated than that. But one thing that we can state with certainty is that for any computer there is a limit on the number of threads that can be run at ...

When programming in Prolog it is not always possible, or desirable, to create predicates which unify for every possible combination of parameters. For example, the predicate between(X,Y,Z) which expresses that Z is numerically between X and Y. It is easily implemented in the cases where X, Y, and Z ...

You can take a look at the full code in this working Plunker. In this example I use a shared service to handle the communication between the pages inside the tab (child pages) and the tab container (the component that holds the tabs). Even though you probably could do it with Events I like the shar...

Gloss is easily installed using the Cabal tool. Having installed Cabal, one can run cabal install gloss to install Gloss. Alternatively the package can be built from source, by downloading the source from Hackage or GitHub, and doing the following: Enter the gloss/gloss-rendering/ directory and ...

Sometimes, programmers who are new to Java make the mistake of defining a class with a name that is the same as a widely used class. For example: package com.example; /** * My string utilities */ public class String { .... } Then they wonder why they get unexpected errors. For ex...

Remove color from an image via ctx.globalCompositeOperation = 'color'; The amount of the effect can be controled with the alpha setting // Render the image ctx.globalCompositeOperation='source-atop'; ctx.drawImage(image, 0, 0); // set the composite operation ctx.globalCompositeOperation='...

Increase the saturation level of an image with ctx.globalCompositeOperation = 'saturation'; The amount of the effect can be controled with the alpha setting or the amount of saturation in the fill overlay // Render the image ctx.globalCompositeOperation='source-atop'; ctx.drawImage(image, 0, ...

Create a colored sepia FX with ctx.globalCompositeOperation = 'luminosity'; In this case the sepia colour is rendered first the the image. The amount of the effect can be controled with the alpha setting or the amount of saturation in the fill overlay // Render the image ctx.globalCompositeOp...

Simple pull When you are working on a remote repository (say, GitHub) with someone else, you will at some point want to share your changes with them. Once they have pushed their changes to a remote repository, you can retrieve those changes by pulling from this repository. git pull Will do it, ...

Detailed instructions on getting wordpress-theming set up or installed. Wordpress is opensource.You can find large set of theme for use free or premium themes.All theme are provide a documentation for install and use. What you have to understand while choose a theme? Wordpress version you are ...

You can use a filter to log only messages "lower" than e.g. ERROR level. But the filter is not supported by PropertyConfigurator. So you must change to XML config to use it. See log4j-Wiki about filters. Example "specific level" <appender name="info-out" class=&quo...

In order to prevent a button from firing multiple times within a short period of time (let's say 2 clicks within 1 second, which may cause serious problems if the flow is not controlled), one can implement a custom SingleClickListener. This ClickListener sets a specific time interval as threshold (...

GRANT SELECT, UPDATE ON Employees TO User1, User2; Grant User1 and User2 permission to perform SELECT and UPDATE operations on table Employees. REVOKE SELECT, UPDATE ON Employees FROM User1, User2; Revoke from User1 and User2 the permission to perform SELECT and UPDATE operations on tab...

PrepareForSegue: func prepareForSegue(_ segue:UIStoryboardSegue, sender sender:AnyObject?) Notifies the view controller that a segue is about to be performed Parameters segue: The segue object. sender: The object that initialized the segue. Example in Swift Perform a task if the ident...