Subject Name: Advanced Web Programming Subject Code: (13MCA43) 1. what is PHP? Discuss different control statements

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1 PES Institute of Technology, Bangalore South Campus (Formerly PES School of Engineering) (Hosur Road, 1KM before Electronic City, Bangalore ) Dept of MCA INTERNAL TEST (SCHEME AND SOLUTION) 2 Subject Name: Advanced Web Programming Subject Code: (13MCA43) 1. what is PHP? Discuss different control statements PHP is mainly focused on server-side scripting, so you can do anything any other CGI program can do, such as collect form data, generate dynamic page content, or send and receive cookies. But PHP can do much more. if, elseif, else if ( ) elseif ( ) else switch switch ( ) case condition1 break; case condition2 break; while Syntax: while (condition) do do while (condition) for Example use of the for statement: for ( $n = 1; $n < 10; $n++) echo "$n<br>"; foreach

2 Versions of PHP prior to version 4 do not support the foreach statement. The following code should list the contents of the array. $tree = array("trunk", "branches", "leaves"); foreach ($tree as $part) echo "Tree part: $part "; break Is used to end the execution of a for, switch, or while statement continue This statement is used to skip the rest of the current loop. for ( $n = 1; $n < 10; $n++) echo "$n<br>"; if ($n == 5) continue; echo "This statement is skipped when $n = 5.<BR>"; 2. Pattren Matching in PHP Regular expressions are nothing more than a sequence or pattern of characters itself. They provide the foundation for pattern-matching functionality. Using regular expression you can search a particular string inside a another string, you can replace one string by another string and you can split a string into many chunks. PHP offers functions specific to two sets of regular expression functions, each corresponding to a certain type of regular expression. You can use any of them based on your comfort. POSIX Regular Expressions PERL Style Regular Expressions POSIX Regular Expressions The structure of a POSIX regular expression is not dissimilar to that of a typical arithmetic expression: various elements (operators) are combined to form more complex expressions. The simplest regular expression is one that matches a single character, such as g, inside strings such as g, haggle, or bag. Lets give explanation for few concepts being used in POSIX regular expression. After that we will introduce you with regular expression related functions. 1. preg_match() The preg_match() function searches string for pattern, returning true if pattern exists, and false otherwise. 2 preg_match_all() The preg_match_all() function matches all occurrences of pattern in string. 3 preg_replace() The preg_replace() function operates just like ereg_replace(), except that regular expressions can be used in the pattern and replacement input parameters.

3 4 preg_split() The preg_split() function operates exactly like split(), except that regular expressions are accepted as input parameters for pattern. 3. Develop an application to track users using cookie $name = $_POST['user']; $pwd = $_POST['pwd']; if ($_POST['on']) if ($name && $pwd) $content = $name."&". $pwd; setcookie("userdetails",$content, time()+120); elseif ($_POST['off']) setcookie("userdetails", ''); <html> <head> <title> Access Control with Cookie </title> </head> <body> <h1> Access Control with cookie </h1> if ($_POST['_check_']) checkform(); else printform(); function checkform() global $name,$pwd; if ($_POST['show']) echo "<h3> cookie contain ". $_COOKIE["UserDetails"]."<h3>";

4 else if(!$name!pwd) echo "<h3> Please enter usename and password </h3>"; else echo "<h3> you submitted $name and $pwd<h3>"; printform(); //checkform function printform() $thisurl = $_SERVER[PHP_SELF]; echo <<<_DONE <form action="$thisurl" method="post"> <table> <td> Enter your Name </td> <td><input type="text" length="20" name="user"></td> <td> password </td> <td><input type ="password" length="10" name="pwd"></td> <td><input type="submit" name="on" value =" Log On"/></td> <td><input type="submit" name="off" value =" Log Off"/></td> <td colspan="2" align="center"> <input type="submit" name="show" value="show the cookie" /> </td> <input type = "hidden" name="_check_" value="1" /> </table> </form>

5 _DONE; </body> </html> 4. Explain functions in PHP PHP functions are similar to other programming languages. A function is a piece of code which takes one more input in the form of parameter and does some processing and returns a value. You already have seen many functions like fopen() and fread() etc. They are built-in functions but PHP gives you option to create your own functions as well. There are two parts which should be clear to you Creating a PHP Function Calling a PHP Function In fact you hardly need to create your own PHP function because there are already more than 1000 of built-in library functions created for different area and you just need to call them according to your requirement. Creating PHP Function Its very easy to create your own PHP function. Suppose you want to create a PHP function which will simply write a simple message on your browser when you will call it. Following example creates a function called writemessage() and then calls it just after creating it. Note that while creating a function its name should start with keyword function and all the PHP code should be put inside and braces as shown in the following example below <html> <head> <title>writing PHP Function</title> </head> <body> /* Defining a PHP Function */ function writemessage() echo "You are really a nice person, Have a nice time!"; /* Calling a PHP Function */ writemessage(); </body> </html> This will display following result You are really a nice person, Have a nice time!

6 4. b. Write a note on file system in PHP Opening a file Reading a file Writing a file Closing a file Opening and Closing Files The PHP fopen() function is used to open a file. It requires two arguments stating first the file name and then mode in which to operate. Files modes can be specified as one of the six options in this table. Mode Purpose r Opens the file for reading only. Places the file pointer at the beginning of the file. r+ Opens the file for reading and writing.places the file w pointer at the beginning of the file. Opens the file for writing only.places the file pointer at the beginning of the file. If files does not exist then it attempts to create a file. w+ Opens the file for reading and writing only.places the file pointer at the beginning of the file. If files does notexist then it attempts to create a file. a Opens the file for writing only.places the file pointer at the end of the file.if files does not exist then it attempts to create a file. a+ Opens the file for reading and writing only.places the file pointer at the end of the file.if files does not exist then it attempts to create a file. fclose() function Reading a file Once a file is opened using fopen() function it can be read with a function called fread(). This function requires two arguments. These must be the file pointer and the length of the file expressed in bytes. Here are the steps required to read a file with PHP. Open a file using fopen() function. Get the file's length using filesize() function. Read the file's content using fread() function. Close the file with fclose() function. The following example assigns the content of a text file to a variable then displays those contents on the web page. //file1.php <html> <head> <title>reading a file using PHP</title> </head> <body> $filename = "tmp.txt"; $file = fopen( $filename, "r" ); if( $file == false ) echo ( "Error in opening file" );

7 exit(); $filesize = filesize( $filename ); $filetext = fread( $file, $filesize ); fclose( $file ); echo ( "File size : $filesize bytes" ); echo ( "<pre>$filetext</pre>" ); </body> </html> WRITING A FILE \\ File2.PHP $filename = "/home/user/guest/newfile.txt"; $file = fopen( $filename, "w" ); if( $file == false ) echo ( "Error in opening new file" ); exit(); fwrite( $file, "This is a simple test\n" ); fclose( $file ); 5. Write a program to track users using session tracking mechanism > session_start(); $name = $_POST['user']; $pwd = $_POST['pwd']; if ($_POST['on']) if ($name && $pwd) $_SESSION['user'] = $name; $_SESSION['pwd'] = $pwd; $_SESSION['counter'] += 1; elseif ($_POST['off']) unset($_session['user']); unset($_session['pwd']); unset($_session['counter']); <html> <head><title> acess control using session </title></head> <body> <h1> access control with sessions </h1> if ($_POST['_check_']) checkform(); else printform(); function checkform()

8 global $name,$pwd; if ($_POST['show']) echo "<h3> session contains ". $_SESSION['user']. " and ". $_SESSION['pwd']. "<h3>"; echo "<h3> you have logged on ". $_SESSION['counter']. " times </h3>"; else if (!$name $pwd ) echo "<h3> please enter user name and pw </h3>"; else echo "<h3> you have entered $name and $pwd <h3>"; printform(); // checkform function printform() $thisurl = $_SERVER[PHP_SELF]; echo <<<_DONE <form action="$thisurl" method="post"> <table> <td> Enter your Name </td> <td><input type="text" length="20" name="user"></td> <td> password </td> <td><input type ="password" length="10" name="pwd"></td> <td><input type="submit" name="on" value =" Log On"/></td> <td><input type="submit" name="off" value =" Log Off"/></td> <td colspan="2" align="center"> <input type="submit" name="show" value="show the Session" /> </td> <input type = "hidden" name="_check_" value="1" /> </table> </form> _DONE; </body> </html> 7. Write a program create XHTML form with Name, address line1, address line2 and text fields. On submitting, store the values in MySQL table. Retrieve and display the data based on name. Refer lab-2 program in Lab manual

Copyright 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley. Chapter 11 Introduction to PHP

Copyright 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley. Chapter 11 Introduction to PHP Chapter 11 Introduction to PHP 11.1 Origin and Uses of PHP Developed by Rasmus Lerdorf in 1994 PHP is a server-side scripting language, embedded in XHTML pages PHP has good support for form processing