Java programming language support these primitive data types:
1. Byte : It is equals to 8 bits
2. Short : (16 bits equals to two bytes)
3. Int : (32 bits equals to 4 bytes)
4. Long : (64 bits equals to 8 bytes)
5. Boolean : Has to possible values either True or False
6. Char :Store a single char
7. Float : (32 bits equals to 4 bytes)
8. Double : (64 bits equals to 8 bytes)
All these data types considered as reserved keywords pre defined by programming language . Primitive values cannot share its state with other primitive values. primitive data types are not object that why we do not use new keyword. There are default values for above types are:
I am going to start with a basic description for java variables because variables in any language are very useful works as a building block for any program , so lets start...
First of all What is meaning of word variable it means not having a fixed pattern. Its a container hold a value for u , When we define a variable with value at beginning of any program after some code we can change value of that variable , of course there are lots of other benefits of variables in java ....so we will describe later.
A variable is also called field so do not confuse . In java we can define variables as :
1. Instance variables
2. Class variables
3. Local variables
1. Instance variables : A variables which also called non static field define with out static keyword and value of instance variable are unique for each instance of a class.
Note : you can not use instance variable in static method till you can not create a object of that class having instance variable.
2. Class variables :A variable with static modifier and value of a static field is same in all over code and we use it by class name do not need to create object.
3. Local variables : A variable only visible to the method where they are declared , no any use of special keyword with local variables.
How we can use these variables:
first we have to define datatype then name of variable end with semicolon like:
int varA ;
now you can assign value to variable here e.g: int varA = 10; or you can assign value where ever you want in code. The advantage of java variable are that we can define and declare a variable any where in the code unlike C.
Object-oriented programming (OOP) is an approach to designing modular, reusable software
systems. Although discussions of object-oriented technology often get mired in the details of one language vs. the other, the real key to the object-oriented approach is that it is a modelling approach first.Although often hyped as a revolutionary way to develop software by zealous proponents, the object-oriented approach is in reality a logical extension of good design practices that go back to the very beginning of computer programming. Object-orientation is simply the logical extension of older techniques such as structured programming and abstract data types. An object is an abstract data type with the addition of polymorphism and inheritance.
Rather than structure programs as code and data, an object-oriented system integrates the two using the concept of an "object". An object has state (data) and behavior (code). Objects correspond to things found in the real world. So for example, a graphics program will have objects such as circle, square, menu. An online shopping system will have objects such as shopping cart, customer,product. The shopping system will support behaviors such as place order, make payment, and offer discount. The objects are designed as class hierarchies. So, for example, with the shopping system there might be high level classes such as electronics product, kitchen product, and book. There may be further refinements for example under electronic products: CD Player, DVD player, etc. These classes and subclasses correspond to sets and subsets in mathematical logic.
The goals of object-oriented programming are:
• Increased understanding.
• Ease of maintenance.
• Ease of evolution.
Hypertext Markup Language, a standardized system for tagging text files to achieve font, color, graphic, and hyperlink effects on World Wide Web pages.
HTML is written in the form of HTML elements consisting of tags enclosed in angle brackets (like <html>), within the web page content. HTML tags most commonly come in pairs like <h1> and </h1>, although some tags represent empty elements and so are unpaired, for example <img>. The first tag in a pair is the start tag, and the second tag is the end tag (they are also called opening tags and closing tags). In between these tags web designers can add text, further tags, comments and other types of text-based content.
The purpose of a web browser is to read HTML documents and compose them into visible or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.
Web browsers can also refer to Cascading Style Sheets (CSS) to define the look and layout of text and other material. The W3C, maintainer of both the HTML and the CSS standards, encourages the use of CSS over explicit presentational HTML.
ASP.NET is a unified Web development model that includes the services necessary for you to build enterprise-class Web applications with a minimum of coding. ASP.NET is part of the .NET Framework, and when coding ASP.NET applications you have access to classes in the .NET Framework. You can code your applications in any language compatible with the common language runtime (CLR), including Microsoft Visual Basic and C#. These languages enable you to develop ASP.NET applications that benefit from the common language runtime, type safety, inheritance, and so on.
If you want to try ASP.NET, you can install Visual Web Developer Express using the Microsoft Web Platform Installer, which is a free tool that makes it simple to download, install, and service components of the Microsoft Web Platform. These components include Visual Web Developer Express, Internet Information Services (IIS), SQL Server Express, and the .NET Framework. All of these are tools that you use to create ASP.NET Web applications. You can also use the Microsoft Web Platform Installer to install open-source ASP.NET and PHP Web applications.
PHP (recursive acronym for PHP: Hypertext Preprocessor) is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML.
Instead of lots of commands to output HTML (as seen in C or Perl), PHP pages contain HTML with embedded code that does "something" (in this case, output "Hi, I'm a PHP script!"). The PHP code is enclosed in special start and end processing instructions <?php and ?> that allow you to jump into and out of "PHP mode."
The best things in using PHP are that it is extremely simple for a newcomer, but offers many advanced features for a professional programmer. Don't be afraid reading the long list of PHP's features. You can jump in, in a short time, and start writing simple scripts in a few hours.
Although PHP's development is focused on server-side scripting, you can do much more with it. Read on, and see more in the What can PHP do? section, or go right to the introductory tutorial if you are only interested in web programming.
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