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Questions tagged [extends]

extends is a keyword in several programming languages used to denote implementation inheritance

extends is a keyword in several programming languages which support object-oriented programming used to denote implementation inheritance (as opposed to implements used to denote interface inheritance).

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Implements vs extends: When to use? What's the difference?

Please explain in an easy to understand language or a link to some article.
Saad Masood
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Extending an Object in Javascript

I am currently transforming from Java to Javascript, and it's a bit hard for me to figure out how to extend objects the way I want it to do. I've seen several people on the internet use a method called extend on object. The code will look like…
Wituz
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What's the difference between 'extends' and 'implements' in TypeScript

I would like to know what Man and Child have in common and how they differ. class Person { name: string; age: number; } class Child extends Person {} class Man implements Person {}
davejoem
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Can I extend a class using more than 1 class in PHP?

If I have several classes with functions that I need but want to store separately for organisation, can I extend a class to have both? i.e. class a extends b extends c edit: I know how to extend classes one at a time, but I'm looking for a method to…
atomicharri
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Can an interface extend multiple interfaces in Java?

Can an interface extend multiple interfaces in Java? This code appears valid in my IDE and it does compile: interface Foo extends Runnable, Set, Comparator { } but I had heard that multiple inheritance was not allowed in Java. Why does…
Prateek
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How do I call a super constructor in Dart?

How do I call a super constructor in Dart? Is it possible to call named super constructors?
Eduardo Copat
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Typescript: How to extend two classes?

I want to save my time and reuse common code across classes that extend PIXI classes (a 2d webGl renderer library). Object Interfaces: module Game.Core { export interface IObject {} export interface IManagedObject extends IObject{ …
Vadorequest
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Extending vs. implementing a pure abstract class in TypeScript

Suppose I have a pure abstract class (that is, an abstract class without any implementation): abstract class A { abstract m(): void; } Like in C# and Java, I can extend the abstract class: class B extends A { m(): void { } } But unlike in…
Michael Liu
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C#'s equivalent of Java's in generics

In Java, I can do the following: (assume Subclass extends Base): ArrayList aList = new ArrayList(); What is the equivalent in C# .NET? There is no ? extends keyword apparently and this does not work: List aList = new…
Louis Rhys
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android how to create my own Activity and extend it?

I need to create a base class that extends Activity which does some common tasks in my application and extend my activities from it,in the following form: public BaseActivity extends Activity{....} public SubActivity extends BaseActivity{...} in…
user173488
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Javascript extends class

What is the right/best way to extend a javascript class so Class B inherits everything from the class A (class B extends A)?
xpepermint
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Difference between extending and intersecting interfaces in TypeScript?

Let's say the following type is defined: interface Shape { color: string; } Now, consider the following ways to add additional properties to this type: Extension interface Square extends Shape { sideLength: number; } Intersection type Square =…
Willem-Aart
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Generics : List is same as List?

I am just trying to understand the extends keyword in Java Generics. List means we can stuff any object in the List which IS A Animal then won't the following also mean the same thing: List Can someone help me know the…
peakit
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Java why interface extends interface

I am wondering under what circumstances do we extend an interface from an interface? Because, for example interface A{ public void method1(); } interface B extends A{ public void method2(); } class C implements B{ @Override public void…
peter
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Why "extends" precedes "implements" in class declaration

Why must implement always be written after extend in a class declaration? For example: public class Register extends ActionSupport implements ModelDriven Why can it not be: public class Register implements ModelDriven extends ActionSupport The…
lzjun
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