Tutorial by Examples: class

By "class", we mean a type that was defined using the class or struct keyword (but not enum struct or enum class). Even an empty class still occupies at least one byte of storage; it will therefore consist purely of padding. This ensures that if p points to an object of an empty class...

Members of objects or classes can be accessed using the object operator (->) and the class operator (::). class MyClass { public $a = 1; public static $b = 2; const C = 3; public function d() { return 4; } public static function e() { return 5; } } $object = new MyCl...

An anonymous inner class is a form of inner class that is declared and instantiated with a single statement. As a consequence, there is no name for the class that can be used elsewhere in the program; i.e. it is anonymous. Anonymous classes are typically used in situations where you need to be abl...

A class written within a method called method local inner class. In that case the scope of the inner class is restricted within the method. A method-local inner class can be instantiated only within the method where the inner class is defined. The example of using method local inner class: public...

A downcast can be used to make use of a subclass's code and data inside of a function taking a parameter of its superclass. class Rat { var color = "white" } class PetRat: Rat { var name = "Spot" } func nameOfRat(🐭: Rat) -> String { guard let petRat = ...

A. The syntax is presented above. The following selector matches all <input> elements in an HTML document that are not disabled and don't have the class .example: HTML: <form> Phone: <input type="tel" class="example"> E-mail: <input type="em...

The :only-child CSS pseudo-class represents any element which is the only child of its parent. HTML: <div> <p>This paragraph is the only child of the div, it will have the color blue</p> </div> <div> <p>This paragraph is one of the two children of the ...

Caffe has a build-in input layer tailored for image classification tasks (i.e., single integer label per input image). This input "Data" layer is built upon an lmdb or leveldb data structure. In order to use "Data" layer one has to construct the data structure with all training d...

We can create a better mapper classes with extension methods, Suppose if i have some DTO classes like public class UserDTO { public AddressDTO Address { get; set; } } public class AddressDTO { public string Name { get; set; } } and i need to map to corresponding v...

Classes and methods are usually defined in the Smalltalk IDE. Classes A class definition looks something like this in the browser: XMLTokenizer subclass: #XMLParser instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'XML-Parser' This is actually...

This basic example shows how an application can instantiate a classloader and use it to dynamically load a class. URL[] urls = new URL[] {new URL("file:/home/me/extras.jar")}; Classloader loader = new URLClassLoader(urls); Class<?> myObjectClass = loader.findClass("com.exampl...

C++11 All standard library containers are left in a valid but unspecified state after being moved from. For example, in the following code, v2 will contain {1, 2, 3, 4} after the move, but v1 is not guaranteed to be empty. int main() { std::vector<int> v1{1, 2, 3, 4}; std::vector&l...

Classification in Machine Learning is the problem that identifies to which set of categories does a new observation belong. Classification falls under the category of Supervised Machine Learning. Any algorithm that implements classification is known as classifier The classifiers supported in P...

Every custom loader must directly or indirectly extend the java.lang.ClassLoader class. The main extension points are the following methods: findClass(String) - overload this method if your classloader follows the standard delegation model for class loading. loadClass(String, boolean) - overloa...

int width = 256; //in pixels int height = 256; //in pixels BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_4BYTE_ABGR); //BufferedImage.TYPE_4BYTE_ABGR - store RGB color and visibility (alpha), see javadoc for more info Graphics g = image.createGraphics(); //draw w...

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...

The standard Java toolchain (and 3rd-party tools designed to interoperate with them) have specific rules for mapping the names of classes to the pathnames of files and other resources that represent them. The mappings are as follows For classes in the default package, the pathnames are simple fi...

The purpose of the classpath is to tell a JVM where to find classes and other resources. The meaning of the classpath and the search process are intertwined. The classpath is a form of search path which specifies a sequence of locations to look for resources. In a standard classpath, these places...

Defining the base class: open class BaseClass { val x = 10 } Defining the derived class: class DerivedClass: BaseClass() { fun foo() { println("x is equal to " + x) } } Using the subclass: fun main(args: Array<String>) { val derivedClass = Deri...

Defining the base class: open class Person { fun jump() { println("Jumping...") } } Defining the derived class: class Ninja: Person() { fun sneak() { println("Sneaking around...") } } The Ninja has access to all of the methods in Pe...