PHP Question Answer

Q1: Answer the following in shortPHP Paper Solution

(a) What is the difference between $name and $$name ?

Ans: $name is a simple variable whereas $$name is a reference variable.

$$name is a variable it’s name is stored in $name.

Example:$name = 'test';$$name = 'xyz'; $test='xyz';

(b) Explain the Define()?

Ans: It is same in c language that it also used to define constant value to the variable

Syntax:

define(name,value,case_sensitive=false)

Name: Required , Specifies the name of the constant

Value: Required, Specifies the value of the constant

case_sensitive: It is optional , It Specifies whether the constant name should be

case_insensitive

The defined () function check whether a constant exits

Return True if the constant exits or false otherwise defined

(c) What is different between single quote String literal & double quote String

literal?

Ans:

Single Quoted Literal:-

The simplest way to specify the a string into enclose it in single quote

e.g:- ‘the character’

In the echo statement the single quote used to display on the browser windows but variable

not expanded occur in the single quoted

e.g :$a=10;echo ‘the number of a = $a’;o/p the number of a = $a

Double Quoted Literal:-

It the String is enclosed in double quoted(“”)

e.g “The String”

It is expanded the occur the variable in double quoted literal

e.g$a=10;echo “the number of a = $a”;o/p the number of a = 10

(d)Explain the terms Die &Return?

Ans :

Die :-

The die and Exit statement both are same working

The Die statement terminated execution of the script

It prints status just before exiting

The status is an integer

Status range is 0 to 254

The status 0 is used to terminated the program successfully

Return:-

The return statement immediately end execution of the current function

The return statement its argument as the value of the function call

Return statement will also end the execution of an eval() statement of an or Script file

(e) What are default session time and path?

Ans:

default session time in PHP is 1440 seconds or 24 minutes

Default session save path id temporary folder /tmp.

(f) What is use of isset() function?

Ans:

In php isset function comes in handy isset is a function that take any variable you want to

use and check to see if it has been set. That is, it has already been assigned a value

eg:<?php if(isset ($_session[‘views’])) $_session[‘views’]=$_session[‘views’]+1;else $_session[‘views’]=1;?>

(g)What is different between function unlink and unset?

Ans :

Unset () Function:- it is mainly used to free the specified session variable

e.g<?php unset($_session[‘views’) ?>

Unlink() Function :- Its mainly used delete the file

Syntax :

unlink(filename,context)

Q2: Answer the following(a) Discuss different Data types in php?

Ans: A Data types refers to the type of data a variable can store. PHP has eight(8) different

data types.

1. Integer number

2. Floating point number

3. Strings

4. Booleans

5. Arrays

6. Objects

7. Resources

8. Null

Integer

The integer data types is use to specify a numeric value without a factorial comment.

You can declare as given bellow

Integer $varabile;

$variable=10;

Real number

It is also known as floating number or floating point number. It is whole number and has

fractions such as 1.22, 2.45, 100.765 etc.

Some examples of valid floating point numbers include:

3.14

0.001

-1.234

0.314E2 // 31.4

1.234E-5//0.00001234

-3.45E-3//-0.00345

Boolean

Boolean values are true or false, also 0 and empty string evaluates to false, and any

numeric value rather than zero, or a string that is not empty evaluates to true.

You can declare as given bellow.

Boolean $variables;

Where Boolean denotes the type of the variable.

Strings

String values are sequence of characters, include in a single quotes, for example,

$strl = “this is a string data type variable”;

A string literal can be specified in four different ways:

1. Single quoted

2. Double quoted

3. Heredoc quoted

4. Now doc quoted

Arrays

An array in PHP is actually ordered map. A map is a type that associates values to keys.

This type is optimized for several different uses; it can be treated as an array, list (vector),

hash table (an implementation of a map), Dictionary, collection, stack, queue, and

probably more.

As array values can be other arrays, trees and multidimensional arrays are also possible.

Resource

Resources are not actual data type, but the storing of a reference to functions and

resources external to PHP.

The most common example of using the resources data type is a data base call.

Null

Null is a special data type which can only have one value, which is itself.

Which is to say, null is not only a data type, but also a key word literal. A variable of data

type null is a variable that has no value assigned to it

OR

Q2: Answer the following

(a)Discuss different types of tables in mysql.

Mysql supports various types of tables or storage engines to allow you To optimize

your database.

The table types are available in MYSQL are:

1. ISAM

2. MYISAM

3. InnoDB

4. BerkleyDB(BDB)

5. MERGE

6. HEAP

1. ISAM :

ISAM had been deprecated and removed from version 5.x. all of

It functionality entire replace by MYISAM. ISAM table has a hard Size 4GB and is not

portable.

2. MYISAM:

MYISAM table type is default when you create table.MYISAM

Table work very fast but not transaction-safe.The size of MYISAM table depends

on the operating system and the data File is portable from system to system.

With MYISAM table type you can have 64 keys per table and maximum key length

of 1024 bytes.

3. InnoDB:

Different from MYISAM table type, innoDB table are transaction safe And supports

row-level locking.

foreign keys are supported in innoDB Tables.

The data file of Innodb table can be stored in more than one File so the size of

table depends on the disk space.

like the MYISAM Table type, data file of InnoDB is portable from system to

system.

The disadvantage of InnoDB in comparison with MyISAM is it take More disk

space.

4. BDB:

BDB is similar to InnoDB in transaction safe.

It supports page level locking But data file are not portable.

5. MERGE:

Merge table type is added to treat multiple MYISAM tables as a single Table so it

remove the size limitation from MYISAM tables.

6. HEAP:

Heap table is stored in memory so it is the fastest one. Because of storage

Mechanism, the data will be lost when the power failure and sometime it cause

the server run out of memory.

Heap tables do not supports columns with AUTO_INCREMENT, BLOB and TEXT

characteristics.

(b)Discuss different loops available in php.

Loops in PHP are used to execute the same block of code a specified number of times, or

while a specified condition is true.

PHP supports four loop types.

1. for

2. while

3. do...While

4. for each

1. for loop:-

The for statements is used when you know how many times you want To execute a

statement or block of statement.

Syntax:

for(initialization; condition; increment)

{

Code to be executed;

}

Example:<?php $test =5; For ($i=1 i<=5 ; i++) {

echo $i;”<br/>”; }?>

Output:

1

2

3

4

5

2. While loop:

The while loop execute a block of code while a condition is true.

Syntax:

while(condition){


}

Example:

<?php $i =0; $num =50; While($i <10) { $sum--; $i++; } echo(“loop stopped at i=$i and num =$sum”);?>

Output:

I = 1;

Num = 40

3. Do…while loop:

The do…while statement will execute a block of code at least Once it then will repeat the

loop as long as a condition is true.

Syntax:

do

{


}while(condition);

Example:<?php

$i=0;

$num=50;

While($i < 10) { $sum—;

$i++; }

echo(“loop stopped at I =$i and num =$num”); ?>

Output:

Loop stop at I = 10

4. for each loop:

The foreach statement is used to loop through arrays. for each Pass the value of the

current array element is assigned to $value and the array pointer is moved by one

and in the next pass next Element will be processed.

Syntax:

foreach(array as value)

{


}

Example:<?php

$array = array(1,2,3,4,5); foreach($array as $value) {

Echo”value is $value <br/>; }

?>

Output:

Value is 1

Value is 2

Value is 3

Value is 4

Value is 5


(a): Discuss any 5 functions of File handling.

Ans : The filesystem functions are used to access and manipulate the filesystem PHP

provides you all the possible functions you may need to manipulate a file.

1) Fopen() function :

The fopen() function opens a file or URL.

Syntax:

fopen(filename,mode)

Mode:

r = Read only

r+ = Read / Write

w = Write only

w+ = Read / Write

a = Append

x = Create a new file.

Example:-<?php

$file=fopen("test.txt","r");

$file=fopen("E:/Sonu/test.txt","r");

?>

2) Fread() function :

The fread() reads from an open file. The function will stop at the end of the file or when it

reaches the specified length,whichever comes first.

Syntax:

fread(file,length)

Example1:-<?php

$file=fopen("test.txt","r") fread($file,"10"); fclose($file);

?>

Example2:-<?php


fread($file,filesize("test.txt"));

// for read entire file...

fclose($file);

?>

3) Fwrite() function :

The fwrite() writes to an open file. The function will stop at the end of the file or when it

reaches the specified length,whichever comes first.

Syntax:

fwrite(file,string,length)

length is optional..

Example:-<?php

$file=fopen("test.txt","r+");

fwrite($file,"Hello");

fclose($file);

?>

4) Fclose() function :

The fclose() function closes an open file. The function returns TRUE on success or FALSE

on failure.

Syntax:

fclose(file)

Example:<?php


// Some code to be executed

fclose($file);

echo ”the file is closed ” ?>

Output:

The file is closed

5) File_exists() function :

The file_exists() function checks whether or not a file or directory exists.

Syntax:

file_exists(path)

Example:-

<?php

echo file_exists("test.txt"); ?>

Output:

The output of the code will be: 1

OR

(A)What is session? Where you will use it in web programming? A PHP session variable is used to store information about, or change settings for a user session. Session variables hold

information about one single user, and are available to all pages in one application.

PHP Session VariablesWhen you are working with an application, you open it, do some changes and then you close it. This is much like a

Session. The computer knows who you are. It knows when you start the application and when you end. But on the internet

there is one problem: the web server does not know who you are and what you do because the HTTP address doesn't

maintain state.

A PHP session solves this problem by allowing you to store user information on the server

for later use (i.e. username, shopping items, etc). However, session information is

temporary and will be deleted after the user has left the website. If you need a permanent

storage you may want to store the data in a database.

Sessions work by creating a unique id (UID) for each visitor and store variables based on

this UID. The UID is either stored in a cookie or is propagated in the URL.

Why Use Session?

As a website becomes more sophisticated, so must the code that backs it. When you get to

a stage where your website needs to pass along user data from one page to another, it

might be time to start thinking about using PHP sessions.

A normal HTML website will not pass data from one page to another. In other words, all

information is forgotten when a new page is loaded. This makes it quite a problem for tasks

like a shopping cart, which requires data (the user's selected product) to be remembered

from one page to the next.

(b) Write a php script to list data in table from database.

<?php

$cn=mysql_connect("localhost","root","");

mysql_select_db("test_db",$cn);

?>

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Database Sample Application</title>

</head>

<body>

<h1 align="center">My First Database Application</h1> <hr size="3" color="#FF0000"/> <table align="center">

<tr bgcolor="#CCCCCC">

<td>Name</td>

<td>Age</td>

</tr>

<?php

$query=mysql_query("select * from student");

while($rs=mysql_fetch_object($query))

{

?>

<tr>

<td><?php echo $rs->s_name;?></td>

<td><?php echo $rs->s_age;?></td>

</tr> <?php

} ?>

</table>

</body>

</html>

OUTPUT:

Q.3(B)Write a php script to list databases available in mysql database server.

<?php

$con=mysql_connect("localhost","root","") or die ('Connection fail..');

$result = mysql_list_dbs($con); while ($row = (mysql_fetch_object($result))) {

echo $row->Database."<br>"; }

mysql_close($con);

?>

OUTPUT:-

information_schema

mysql

performance_schema

test

test_db

Q3(C) How Comments are given in php code?

http://www.bcarocks.com/wp-content/uploads/2013/07/myfirstdatabase_app.png

Ans :

While there is only one type of comment in HTML, PHP has two types.

The first type we will discuss is the single line comment. The single line comment tells the

interpreter to ignore everything that occurs on that line to the right of the comment.

for single line comment type "//" or "#" and all text to the right will be ignored by PHP

interpreter.

PHP Code:<?php

echo "Hello World!"; // This will print out Hello World! // echo "Hello India";

# echo "Hello India"; ?>

Similar to the HTML comment, the multi-line PHP comment can be used to comment out

large blocks of code or writing multiple line comments. The multiple line PHP comment

begins with " /* " and ends with " */ ".<?php

echo "Hello World!"; /* echo "Hello India";

echo "Hello World";

*/

?>


(a) List all input elements. Explain any two with example.

Ans: Input elements are as follows:

There are many input elements for INPUT type like

1. Textbox

2. Hidden fields

3. Password fields

4. Checkbox

5. Radio Button

6. Image

7. Button

8. Submit

9. Reset

OR

(a) How array are created in PHP? Discuss any three sorting Function of array?

Ans .

Arrays provide a way to store much larger amounts of data without having many separate

named variables.

If a normal variable where data can be stored, a simple array is like a row where lots of

data can be stored.

Normal variables have names like $test

An array variable is named with square brackets. Here is an example $test[]

Each element in the array has its own index so that it can be easily accessed.

You can use it either as a simple c like array or as an associative array.

Here array indices are enclosed into [] rather than {}.

Rather than having a fixed number of slots, php creates array slots as new elements are

added to the array.

You can assign any type for keys and values. Such as string, float ,integer etc.

In PHP, there are three kinds of arrays:

o Numeric array - An array with a numeric index

o Associative array - An array where each ID key is associated with a value

o Multidimensional array - An array containing one or more arrays

1.Numeric array

A numeric array stores each array element with a numeric index.

There are two methods to create a numeric array.

1. In the following example the index are automatically assigned (the index starts at 0):

<?php

$names=array("Juned Sir"," Nishant"," Karishma"," Mayur");

?>

2. In the following example we assign the index manually:

<?php

$names[0]="JunedSir";

$names[1]="Nishant";

$names[2]="Karishma";

$names[3]="Mayur";

?>

2.Associative array :

An associative array, each ID key is associated with a value.

When storing data about specific named values, a numerical array is not always the best

way to do it.

With associative arrays we can use the values as keys and assign values to them.

<?php

$ages = array("Nishant"=>20, "Mayur"=>19, "Karishma"=>21);

?>

3.Multidimensional array

In a multidimensional array, each element in the main array can also be an array.

And each element in the sub-array can be an array, and so on.<?php

$faculties=array

( "BCA"=>array ( "JunedSir", "MaulikSir", "KirtiMadam" ), "BBA"=>array ( "ShamaMadam" ), "BCOM"=>array ( "NehaMadam", "BhumikaMedam", "RadhikaMadam" ) );

?>

The array above would look like this if written to the output:<?php

Array([BCA] => Array ( [0] => Juned Sir [1] => Maulik Sir [2] => Kirti Madam )[BBA] => Array ( [0] => Shama Madam

)[BCOM] => Array ( [0] => Neha Madam [1] => Bhumika Medam [2] => Radhika Madam ))

?>

Three sorting functions of an array :

1) sort()

Sort an array by the values.

Syntax :

sort(array)

Example: <?php

$fruits = array("lemon", "orange", "banana", "apple");sort($fruits);

print_r($fruits);

?>

The output of the code above will be:

Array ( [0] => apple [1] => banana [2] => lemon [3] => orange ) 2) rsort()

sorts an array by the values in reverse order.

Syntax:

rsort(array) Example:

<?php

$fruits = array("lemon", "orange", "banana", "apple");rsort($fruits);

print_r($fruits);

?>


Array ( [0] => orange [1] => lemon [2] => banana [3] => apple )

3) asort()

The asort() function sorts an array by the values. The values keep their original keys.

Syntax:

asort(array)

Example:

<?php$fruits = array("lemon", "orange", "banana", "apple");asort($fruits);

print_r($fruits);

?>


Array ( [3] => apple [2] => banana [0] => lemon [1] => orange )

4) arsort()

sorts an array by the values in reverse order. The values keep their original keys.

Syntax:

arsort(array,sorttype) Example:

<?php

$fruits = array("lemon", "orange", "banana", "apple");arsort($fruits);

print_r($fruits);

?>


Array ( [1] => orange [0] => lemon [2] => banana [3] => apple )

Q.4(C) Write a script to fill the combo box from mysql database.<?php$cn=mysql_connect("localhost","root","");mysql_select_db("test_db",$cn);?><html><body> <select name="mycombo"> <?php $query=mysql_query("select * from student"); while($rs=mysql_fetch_object($query)) { ?> <option><?php echo $rs->s_name;?></option> <?php } ?> </select></body></html>

?1

Output:

OR

Q.4(B). Write a script for login page with validations.<?php$cn=mysql_connect("localhost","root","");mysql_select_db("test_db",$cn);?><html><body><h1 align="center">My Login Page</h1>

<hr size="3" color="#FF0000"/> <script language="javascript"> function checkfrm() { if(document.frmlogin.txtlogin.value == "") { alert("Please Enter User Name.."); document.frmlogin.txtlogin.focus(); return false; } if(document.frmlogin.txtpassword.value == "") { alert("Please Enter Password.."); document.frmlogin.txtpassword.focus(); return false; }

return true; } </script> <?php if(isset($_POST['submit'])) { $sql = "select * from login where username='".$_POST['txtlogin']."' and password='".$_POST['txtpassword']."'"; $rs = mysql_query($sql); if(mysql_num_rows($rs) > 0) { header("location:welcome.php"); } else { echo "Invalid Login"; } } ?> <form name="frmlogin" method="post" onsubmit="return checkfrm()"> <table align="center">

http://www.bcarocks.com/wp-content/uploads/2013/07/combobox_from_database.jpg

<tr> <td>User Name:</td> <td><input type="text" name="txtlogin" /></td> </tr> <tr> <td>Password:</td>

<td><input type="password" name="txtpassword" /></td> </tr> <tr> <td></td> <td align="center"> <input type="submit" name="submit" value="Login" /> <input type="reset" /></td> </tr> </table> </form></body></html>

<strong>Output:</strong>

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