PHP is a server scripting language, and a powerful tool for making dynamic and interactive Web pages.

A regular expression is a sequence of characters that define a search pattern. In javascript, regex use the delimiter `/`.

Digital image processing is the use of a digital computer to process digital images through an algorithm. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.

Data link layer has responsibility of transferring data (a frame) from one node to adjacent node over a link. Make sure the transition is error-free. It needs to check the error.

In this note, you will quickly know about the Abstract Classes and Interfaces. Abstract class is a restricted class that cannot be used to create objects (to access it, it must be inherited from another class), while Interface is a completely "abstract class" that contains only constants and abstract methods.

In this note, you will quickly know about the static modifier on variables, constants and methods. Static variables are shared by all the instances of the class. Static methods are not tied to a specific object.

Data link layer has responsibility of transferring data (a frame) from one node to adjacent node over a link. Make sure the transition is error-free. It needs to check the error.

Inheritance is implemented on the classes whereas, the polymorphism is implemented on methods/functions. Polymorphism in Java has two types, Runtime polymorphism (dynamic binding) and Compile time polymorphism (static binding).

Inheritance is used to avoid redundancy when Classes have many common features. The idea is to develop a subclass from a superclass.

Swift is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. and the open-source community, first released in 2014. According to Apple, Swift is “friendly” to new programmers.