Java Variable concepts

What is variable?

Variable is a container, which is used to hold some value in itself. This value can be int , float, string, Boolean  etc.

Declaration of variable in java.

Variables in java can be declared as

Syntax  

Variable_type  variable_name ;

Example

Public int  var1;</pre>
/* public is access modifier */

Public final int var2;

/* final is non-access modifier */

 

Initialization of variable in java

Above we have defined only variables and now it is time to initialize the varable. Initialization means assigning value to variables.

Example

Public int  var1=2;
Public final int var2=10;

Declaration And Initialization To gather

Public int  var1=2 var3,var4=33;
/*var1,var3 var4 declared and var1 and var4 are initialized*/

Assigning Octal,Decimal and Hexadecimal Values To Variables

int  decimal1 = 33;/*assigning decimal format values to varaible*/
int octal2 = 012;/*assigning octal format values to varaible*/
int hexa3 = 0xb;/*assigning hexadecimal format values to varaible*/

Data types

java has several data types that are widely used.Every variable should have its type defined because Java is strongly typed language (i.e) variables data types compatibility is strongly monitored.

There are two types of data types in Java

  • Primitive Data Types
  • Reference Data Types

 Primitive Data Types

  1. byte
  2. short
  3. int
  4. long
  5. float
  6. double
  7. char
  8. boolean

Reference Data Types

the address of array or objects created in memory is called reference data types because these addresses are stored in the variables that are also called reference variables.

Static and Dynamic webpages

PHP & MySQL Course:

I am going to start a Dynamic Website developing course, in which you will learn each and every thing about PHP & MySQL in step by step procedures.

Lecture 1:

It is the first lecture in which we learn the importance of the PHP & MySQL. PHP stands for   PHP Hyper Text Preprocessor. As we know that there are two types of website Web Pages.

  1. Static Web Pages.
  2. Dynamic Web Pages.

Static Web Pages:

In Static Web Pages, the data is Static. It does not change, because it is not connected with the database.

Dynamic Web Pages:

In Dynamic Web Pages, the data is Dynamic. And the retrieve from the database during the time of browsing. And it is very secure, if we design Dynamic web pages. Because our data will communicate with database and attacking on the servers is not a piece of cake.

Integration Development Environment (IDE) For PHP & MySQL:

If we want to start website designing with the help of PHP & MySQL. So we just need to use a simple text editor for PHP & MySQL. We can use other IDE for PHP & MySQL programming, as if we want use an artificial intelligence. So we need to use Dreamweaver, Netbeans etc. There are many other IDE which can be used for the PHP & MySQL programming in a Dynamic Website development.

For your learning purpose you should use a simple IDE, in which you feel to learn and keep them in your mind. Don’t forget them because they will need to be used on any time and any place.

Server & Database For PHP & MySQL Programming:

As we know that PHP is a sever side programming language. And it needs a server which hosts the Dynamic Web Pages which are programmed with PHP & MySQL. And we also need a database application for the MySQL to communicate with the database during the browsing of Dynamic Web Pages. In this PHP & MySQL course we will use two application which are being used mostly by PHP & MySQL programmers i.e. Xampp Apache for PHP and Navicat for MySQL.

Links for PHP & MySQL Applications for the Course:

For Xampp use this link to download it, http://www.apachefriends.org. And use this link for Navicat MySQL use this link to download it, http://www.navicat.com/download

NOTE:

We can also use the Xampp for the MySQL, because Xampp is that application which provide us everything, which could be needed during the development of a dynamic website. But the use of the Xampp for Database is little bit difficult. And if we use the Navicat for MySQL so it will be much easier than the Xampp as a database application.

Local host server:

There is a problem with new website developers, it happens usually at the beginning when they start from the scratch of the website development. That is hosting, we need a place where we can host our website and the visitors will able to browse the website. According to this course we need a server which host our dynamic web pages, and we can visit them fully free. So that is Xampp which we discussed it previous paragraphs. It will create our local machine or Local PC as a local Host Server. And we will use it to save our dynamic web pages directly to its directory and we can access our dynamic web pages which we designed.

And at the run time or during the browsing of the web pages we will know the errors and use of the website. In the designing or development of anything, every time we need to take care of the users or visitors. Because we know each and every thing about the system. How it will work and for which purpose it is going to be design.

FTP (File Transfer Protocol):

When we fully designed the website. And when we feel that now it is the time to upload the website on the Internet. There are few steps when we want to upload our website;

  1. Buy a Hosting from any good Server which you think that it is best for your website.
  2. Register a Domain (Name of the Your Website).

After these two things, now we can use the FTP to upload our website on the server which we bought for our website purpose. We will read these all things in details but after the completion of the PHP and & MySQL programming course.

Summary:

In this lecture, we learnt about the basics of the website development. As we just reviewed the basics of the Dynamic Web site development. We discussed the types of Web Pages, IDE for PHP & MySQL etc. And also we reviewed the Local Host server and also FTP.

These things are the basics of the Dynamic Website development. We should know about these things. As you heard about the CMS (Content Management System) we use them for Dynamic Website creation. And which things we discussed in this lecture these all things are need to design a CMS for your own purpose. If you read all the lectures of this course so you will be able to design your own CMS to use it for your future Website development in a simple and easy way.

One thing I should tell you in the start of this course, I will use Notepad++ as IDE in this course. Because if you are new so you should as simple IDE as your programming environment, from which you feel to learn and remember every function. If you use a High Quality IDE as there are Dreamweaver and Netbeans for the PHP programming so you will use artificial intelligence of them. And you will not learn anything. You will be used to of those IDE. Because these IDE provide you many things which you need for Website development.

I hope you learn something from the first lecture and now you should set your mind for the Installations of the Environments. Because now we will download and install the applications which we discussed in this lecture.

Introduction To C++

C++ programming Language.It is one of the most  powerful  Programming language. it was developed by Bjarne Stroustrup at BELL laboratories. C++ is actually developed as an extension of C. In 1998 C++ was standardised by the International Standard Organisation(ISO).Most of the Operating Systems are designed in c++ .Since it was developed a system based Language.

Now in this series of articles we will first learn the Basics of c++ , and then move to advance concepts of programming such as polymorphism ,template and use of Algorithms.

(IDE) (integrated development environment)

There are many IDEs but what we prefer is an easy and simply IDE best for beginners you can download the IDE from the link given  http://download.cnet.com/C-Free/3000-2212_4-10311060.html.

IDE

 

Its installation is very simple just like ordinary software.

Before writing a program we would like to spend a few minutes describing what compiler is ?

What is Complier?

We know that computer is dumb machine it  can only understand machine Language that comprises of 0s and 1s. But if you look at any programming language that is more like English language and can be understood by human it is called high level Language. Now the question arises that , how then computer understand the program we write ,it is here ,when we need Compiler. Complier is set of programs that are used to translate the high level language into lower level Language or machine code in order to form a executable programs , that can  be directly run on computer.

The code or programme which we write is called Source code.

Consider the diagramgiven below . The code which we write building a any program is compiled and executable or exe fileis created that can be run on computer just bydouble clicking on it .

Capture22

 What  is  An Interpreter?

It is a program that reads your source  code compiles and executes (interprets) it as it is run.

It is required every time you run your program. Every time the source code is compiled and executed there is no executable files generated as that is generated by compiler. So than what is the advantage if interpreter?

Its advantage is that its construction is comparatively easy as it can be built in high level language.

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