Rizwan Abbasi’s Blog











{مارچ 12, 2006}   Beginning ASP

Beginning ASP is pretty easy. ASP is a kool language for creating dynamic webpages.

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{مارچ 10, 2006}   3rd Lecture.

You cannot view the PHP source code by selecting "View source” in the browser – you will only see the output from the PHP file, which is plain HTML. This is because the scripts are executed on the server before the result is sent back to the browser.


Basic PHP Syntax

A PHP file normally contains HTML tags, just like an HTML file, and some PHP scripting code.
Below, we have an example of a simple PHP script which sends the text "Hello World” to the browser:

 
 
 
 
 

A PHP scripting block always starts with and ends with ?>. A PHP scripting block can be placed anywhere in the document.
Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another.
There are two basic statements to output text with PHP: echo and print. In the example above we have used the echo statement to output the text "Hello World”.


Variables in PHP

All variables in PHP start with a $ sign symbol. Variables may contain strings, numbers, or arrays.
Below, the PHP script assigns the string "Hello World” to a variable called $txt:

 
 

$txt="Hello World"; 
echo $txt; 
?> 
 
 

To concatenate two or more variables together, use the dot (.) operator:

 
 

$txt1="Hello World"; 
$txt2="1234"; 
echo $txt1 . " " . $txt2 ; 
?> 
 
 

The output of the script above will be: "Hello World 1234”.


Comments in PHP

In PHP, we use // to make a single-line comment or /* and */ to make a large comment block.

 
 

//This is a comment 
/* 
This is 
a comment 
block 
*/ 
?> 
 
 



{مارچ 10, 2006}   2nd Lecture

What do You Need?  

This tutorial will not explain how to install PHP, MySQL, or Apache Server. 

If your server supports PHP – you don’t need to do anything! You do not need to compile anything or install any extra tools  – just create some .php files in your web directory – and the server will parse them for you. Most web hosts offer PHP support. 

However, if your server does not support PHP, you must install PHP. Below is a link to a good tutorial from Webmonkey on how to install PHP4: 

http://hotwired.lycos.com/webmonkey/00/44/index4a.html?tw=programming 

Download PHP  

Download PHP for free here: http://www.php.net/downloads.php 

Download MySQL Database  

Download MySQL for free here: http://www.mysql.com/downloads/index.html 

Download Apache Server  

Download Apache for free here: http://httpd.apache.org/download.cgi



{مارچ 10, 2006}   First Lecture

A PHP file may contain text, HTML tags and scripts. Scripts in a PHP file are executed on the server. 


What you should already know  

Before you continue you should have some basic understanding of the following: 

  • WWW, HTML and the basics of building Web pages 
  • Some scripting knowledge 

If you want to study these subjects, go to our Home Page 


What is PHP?  

  • PHP stands for PHP: Hypertext Preprocessor 
  • PHP is a server-side scripting language, like ASP 
  • PHP scripts are executed on the server 
  • PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) 
  • PHP is an open source software (OSS) 
  • PHP is free to download and use 

What is a PHP File?  

  • PHP files may contain text, HTML tags and scripts 
  • PHP files are returned to the browser as plain HTML  
  • PHP files have a file extension of ".php”, ".php3”, or ".phtml” 

What is MySQL?  

  • MySQL is a small database server 
  • MySQL is ideal for small and medium applications 
  • MySQL supports standard SQL 
  • MySQL compiles on a number of platforms 
  • MySQL is free to download and use 

PHP + MySQL  

  • PHP combined with MySQL are cross-platform (means that you can develop in Windows and serve on a Unix platform) 

Why PHP?  

  • PHP runs on different platforms (Windows, Linux, Unix, etc.) 
  • PHP is compatible with almost all servers used today (Apache, IIS, etc.) 
  • PHP is FREE to download from the official PHP resource: www.php.net 
  • PHP is easy to learn and runs efficiently on the server side 

Where to Start?  

  • Install an Apache server on a Windows or Linux machine 
  • Install PHP on a Windows or Linux machine 
  • Install MySQL on a Windows or Linux machine 


{مارچ 5, 2006}   4th Lecture.

Operators are used to operate on values.


PHP Operators

This section lists the different operators used in PHP.
Arithmetic Operators

Operator
Description
Example
Result
+ Addition x=2
x+2
4
Subtraction x=2
5-x
3
* Multiplication x=4
x*5
20
/ Division 15/5
5/2
3
2.5
% Modulus (division remainder) 5%2
10%8
10%2
1
2
0
++ Increment x=5
x++
x=6
Decrement x=5
x–
x=4

Assignment Operators

Operator
Example
Is The Same As
= x=y x=y
+= x+=y x=x+y
-= x-=y x=x-y
*= x*=y x=x*y
/= x/=y x=x/y
%= x%=y x=x%y

Comparison Operators

Operator
Description
Example
== is equal to 5==8 returns false
!= is not equal 5!=8 returns true
> is greater than 5>8 returns false
  is less than 5
>= is greater than or equal to 5>=8 returns false
  is less than or equal to 5

Logical Operators

Operator
Description
Example
&& and x=6
y=3
(x 1) returns true
|| or x=6
y=3
(x==5 || y==5) returns false
! not x=6
y=3
!(x==y) returns true


{مارچ 5, 2006}   5th Lecture

Conditional statements in PHP are used to perform different actions based on different conditions.


Conditional Statements

Very often when you write code, you want to perform different actions for different decisions. You can use conditional statements in your code to do this.
In PHP we have two conditional statements:

  • if (…else) statement – use this statement if you want to execute a set of code when a condition is true (and another if the condition is not true)
  • switch statement – use this statement if you want to select one of many sets of lines to execute

The If Statement

If you want to execute some code if a condition is true and another code if a condition is false, use the if….else statement.

Syntax

if (condition) 
code to be executed if condition is true; 
else 
code to be executed if condition is false; 

Example

The following example will output "Have a nice weekend!” if the current day is Friday, otherwise it will output "Have a nice day!”:

 
 

$d=date("D"); 
if ($d=="Fri") 
echo "Have a nice weekend!"; 
else 
echo "Have a nice day!"; 
?> 
 
 

If more than one line should be executed when a condition is true, the lines should be enclosed within curly braces:

 
 

$x=10; 
if ($x==10) 
{ 
echo "Hello "; 
echo "Good morning "; 
} 
?> 
 
 


The Switch Statement

If you want to select one of many blocks of code to be executed, use the Switch statement.

Syntax

switch (expression) 
{ 
case label1: 
  code to be executed if expression = label1; 
  break;  
case label2: 
  code to be executed if expression = label2; 
  break; 
default: 
  code to be executed 
  if expression is different 
  from both label1 and label2; 
} 

Example

This is how it works: First we have a single expression (most often a variable), that is evaluated once. The value of the expression is then compared with the values for each case in the structure. If there is a match, the block of code associated with that case is executed. Use break to prevent the code from running into the next case automatically. The default statement is used if none of the cases are true.

 
 

switch ($x) 
{ 
case 1: 
  echo "Number 1"; 
  break; 
case 2: 
  echo "Number 2"; 
  break; 
case 3: 
  echo "Number 3"; 
  break; 
default: 
  echo "No number between 1 and 3"; 
} 
?> 
 
 



{مارچ 1, 2006}   Rizwan Abbasi

I am Rizwan Abbasi. Today is 2nd of March 2006. It’s 01:27AM. I am learning now SQL (Structured Query Language) and also talking to Fahdi.



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