PHP Part-2

Hi friends, this is my second blog on PHP and today we will learn about:

• How to create and store variables?
• What echo do?
•  How to give comment?
• What is heredoc?

Variable: By using variables we can store strings, a word or a number. In PHP, data types are assigned automatically. There is no need to assign data types manually.   

Variable form:

          $variable_name=value;

This variable name is case sensitive. There are some standard ways to write variable name:

1.     Name of the variable must start with alphabetic word or “_”.

2.     Variable name must consist only of alpha-numeric words and underscores.

3.     If there is more than one word in variable then it must be separated by “_” or by capitalization.

    Echo: Echo is used to output the string. Echo uses quotes (“ “) to define beginning and end of the string. At the time of echoing variable there is no need for quotations.

    Comment: Comments are used to document the project or code.

For single line comments (//) are used and for multiline comments (/*……….*/).

 String: There are two types of strings:

1.     Stored string: $my_string= ”Hey Jak”;

echo $my_string;

2.     Direct string: echo “ Hi Jak “;

Strings are quoted in two ways, double quotes (“ ”) and single quotes(‘ ‘).

 sHeredoc: This is the unique feature of PHP, it lets programmer create multi-line strings without using quotes. It begin with (<<<) and some identifier and it ends with identifier followed by semi-colon (;).

 Example: example demonstrating use of variable, comment, echo and heredoc.

Introduction to PHP and its basic syntax

Hi friends, today we will see introduction to PHP and its basic syntax. Prerequisite to understand this blog is to read my previous blog on XAMPP server.

PHP is the recursive acronym for PHP: Hypertext Pre-processor. PHP was developed by Rasmus Lerdorf and now it is maintained by The PHP Group. It is an open source server side scripting language. Pre-requisite for learning PHP is HTML. PHP code can be embedded inside HTML code. PHP is mainly used for web development. Everything in PHP is enclosed in angle brackets

“<?php ……………..?> “.

PHP allows writing web pages which are dynamically generated. When a user visits any of the website which has PHP webpage’s, then a web server processes the PHP code and translate it into HTML page and then send to the requesting client.

PHP’s syntax is very similar to C, Perl, Java beside this PHP code can also contains tags.

PHP code is:

<?php

------

------

?>

PHP code must be saved with the .php extension. We will now see a simple Hello World program written in PHP which will give us basic understanding about the syntax of PHP that we must use.

This simple code is saved in the xampp directory where the path is C:\xampp\htdocs\hello_world.php. We have seen xampp in our previous blog, so start apache server there. And then go to web browser and type localhost/Hello_World.php.

Output:

There are several things to learn from this simple code written above. As we can see, code which is red in colour is the starting and end point of php code. Everything will be inside this code always. Now see line 2, echo is used to print the statement that follows, be careful here to end the statement with semicolon (;).

This is the first blog on PHP and in coming weeks we will learn more about this dynamic language.

XAMPP: A web server package

XAMPP is a cross platform web server package. Cross platform means it works on every possible operating system without any compatibility issues. XAMPP is the acronym for: X-cross platform, A- Apache HTTP server, M- MySQL, P-PHP, P- Perl. The main advantage of XAMPP is that it requires very less configuration for its components, which make it quite user friendly. The default FTP user for XAMPP is "newuser", and default FTP password is "wampp". Similarly default MySQL user is "root", and there is no default password for MySQL.

XAMPP contains its own XAMPP Control Panel, where all the modules and their current status is given. We can very easily start or stop any module which we want, by clicking on "Action" button beside modules. We can even configure the modules. A small pop-up screen appears when we click on "config" button.

There is one main config button on top right side.  When we click on that main config button on top right corner then the following window will appear.

Below all this modules there is a terminal which displays the actions and generate a log file which we can view by clicking on logs. There are several different XAMPP distributions, 1. XAMPP for Linux, 2. XAMPP for Windows, 3. XAMPP for Mac OS X, 4. XAMPP for SOLARIS. Installing XAMPP is also very simple task in windows 8 just download the zip file and extract it and double click on .exe file. The folder name xampp will be created in C drive. So basically XAMPP is very user friendly and easy to use cross platform web server.

XAMPP is developed by Apache Friends and the Official website for XAMPP is  www.apachefriends.org/en/xampp.html