Tutorial by Examples: u

With C++11 and higher calculations at compile time can be much easier. For example calculating the power of a given number at compile time will be following: template <typename T> constexpr T calculatePower(T value, unsigned power) { return power == 0 ? 1 : value * calculatePower(value,...

Access ModifierVisibilityInheritancePrivateClass onlyCan't be inheritedNo modifier / PackageIn packageAvailable if subclass in packageProtectedIn packageAvailable in subclassPublicEverywhereAvailable in subclass There was once a private protected (both keywords at once) modifier that could be appli...

Haskell is a pure language, meaning that expressions cannot have side effects. A side effect is anything that the expression or function does other than produce a value, for example, modify a global counter or print to standard output. In Haskell, side-effectful computations (specifically, those wh...

Here is how to make a Heads Up Notification for capable devices, and use a Ticker for older devices. // Tapping the Notification will open up MainActivity Intent i = new Intent(this, MainActivity.class); // an action to use later // defined as an app constant: // public static final String ME...

Using Razor @functions keyword gives the capability of introducing classes and methods for inline use within a Razor file: @functions { string GetCssClass(Status status) { switch (status) { case Status.Success: return "alert-success&qu...

App::uses('YourModel', 'Model'); $model_1 = new YourModel(array('ds' => 'default')); $model_2 = new YourModel(array('ds' => 'database2'));

We can use partial application to "lock" the first argument. After applying one argument we are left with a function which expects one more argument before returning the result. (+) :: Int -> Int -> Int addOne :: Int -> Int addOne = (+) 1 We can then use addOne in order to...

Returning partially applied functions is one technique to write concise code. add :: Int -> Int -> Int add x = (+x) add 5 2 In this example (+x) is a partially applied function. Notice that the second parameter to the add function does not need to be specified in the function definitio...

If a type wishes to have value semantics, and it needs to store objects that are dynamically allocated, then on copy operations, the type will need to allocate new copies of those objects. It must also do this for copy assignment. This kind of copying is called a "deep copy". It effective...

To access pixel values in an OpenCV cv::Mat object, you first have to know the type of your matrix. The most common types are: CV_8UC1 for 8-bit 1-channel grayscale images; CV_32FC1 for 32-bit floating point 1-channel grayscale images; CV_8UC3 for 8-bit 3-channel color images; and CV_32FC3 ...

Use to push commits made on your local branch to a remote repository. The git push command takes two arguments: A remote name, for example, origin A branch name, for example, master For example: git push <REMOTENAME> <BRANCHNAME> As an example, you usually run git push orig...

Sometimes two arrays of the same length need to be iterated together, for example: $people = ['Tim', 'Tony', 'Turanga']; $foods = ['chicken', 'beef', 'slurm']; array_map is the simplest way to accomplish this: array_map(function($person, $food) { return "$person likes $food\n"; ...

Prelude is another popular starter kit. It features good support for various programming languages out-of-the-box including, notably - clojure. On *nix systems it can be installed with the following command: curl -L https://git.io/epre | sh

Model using System.ComponentModel.DataAnnotations; public class ViewModel { [Required(ErrorMessage="Name is required")] public string Name { get; set; } [StringLength(14, MinimumLength = 14, ErrorMessage = "Invalid Phone Number")] [Required(ErrorMessag...

To install packages directly from GitHub use the devtools package: library(devtools) install_github("authorName/repositoryName") To install ggplot2 from github: devtools::install_github("tidyverse/ggplot2") The above command will install the version of ggplot2 that corre...

We have to create a view which will have a image prefix to a text. text could be of variable length.We have to achieve a result where in Image + text is always in center of a parent view. Step 1: First create a single view project and name it something of your choice and open the story board fist...

In case your project needs to be based on a specific Symfony version, use the optional second argument of the new command: # use the most recent version in any Symfony branch $ symfony new my_project_name 2.8 $ symfony new my_project_name 3.1 # use a specific Symfony version $ symfony new my_...

Open your command console and execute the following commands: $ sudo curl -LsS https://symfony.com/installer -o /usr/local/bin/symfony $ sudo chmod a+x /usr/local/bin/symfony

Given any value of type Int or Long to render a human readable string: fun Long.humanReadable(): String { if (this <= 0) return "0" val units = arrayOf("B", "KB", "MB", "GB", "TB", "EB") val digitGroups = (Mat...

In Kotlin you could write code like: val x: Path = Paths.get("dirName").apply { if (Files.notExists(this)) throw IllegalStateException("The important file does not exist") } But the use of apply is not that clear as to your intent. Sometimes it is clearer to create a ...