PHP Interview question and answer

PHP

What's PHP
The PHP Hypertext Preprocessor is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web based software applications.

What Is a Session?
A session is a logical object created by the PHP engine to allow you to preserve data across subsequent HTTP requests.
There is only one session object available to your PHP scripts at any time. Data saved to the session by a script can be retrieved by the same script or another script when requested from the same visitor.
Sessions are commonly used to store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same visitor.

What is meant by PEAR in php?
Answer1:
PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard, and packing the strength and experience of PHP users into a nicely organized OOP library. PEAR also provides a command-line interface that can be used to automatically install "packages"

Answer2:
PEAR is short for "PHP Extension and Application Repository" and is pronounced just like the fruit. The purpose of PEAR is to provide:
A structured library of open-sourced code for PHP users
A system for code distribution and package maintenance
A standard style for code written in PHP
The PHP Foundation Classes (PFC),
The PHP Extension Community Library (PECL),
A web site, mailing lists and download mirrors to support the PHP/PEAR community
PEAR is a community-driven project with the PEAR Group as the governing body. The project has been founded by Stig S. Bakken in 1999 and quite a lot of people have joined the project since then.

How can we know the number of days between two given dates using PHP?
Simple arithmetic:

$date1 = date('Y-m-d');
$date2 = '2006-07-01';
$days = (strtotime() - strtotime()) / (60 * 60 * 24);
echo "Number of days since '2006-07-01': $days";

How can we repair a MySQL table?
The syntex for repairing a mysql table is:

REPAIR TABLE tablename
REPAIR TABLE tablename QUICK
REPAIR TABLE tablename EXTENDED

This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.

What Is a Persistent Cookie?
A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's computer. By default, cookies are created as temporary cookies which stored only in the browser's memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:

• Temporary cookies can not be used for tracking long-term information.
• Persistent cookies can be used for tracking long-term information.
• Temporary cookies are safer because no programs other than the browser can access them.
• Persistent cookies are less secure because users can open cookie files see the cookie values.

How To Write the FORM Tag Correctly for Uploading Files?
When users clicks the submit button, files specified in the <INPUT TYPE=FILE...> will be transferred from the browser to the Web server. This transferring (uploading) process is controlled by a properly written <FORM...> tag as:
<FORM ACTION=receiving.php METHOD=post ENCTYPE=multipart/form-data>

What are the differences between require and include, include_once?
Anwser 1:
require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.

But require() and include() will do it as many times they are asked to do.

Anwser 2:
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. The major difference between include() and require() is that in failure include() produces a warning message whereas require() produces a fatal errors.

Anwser 3:
All three are used to an include file into the current page.
If the file is not present, require(), calls a fatal error, while in include() does not.
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. It des not call a fatal error if file not exists. require_once() does the same as include_once(), but it calls a fatal error if file not exists.

Anwser 4:
File will not be included more than once. If we want to include a file once only and further calling of the file will be ignored then we have to use the PHP function include_once(). This will prevent problems with function redefinitions, variable value reassignments, etc.

What is meant by urlencode and urldecode?
Anwser 1:
urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode("10.00%") will return "10%2E00%25". URL encoded strings are safe to be used as part of URLs.
urldecode() returns the URL decoded version of the given string.

How To Get the Uploaded File Information in the Receiving Script?
Once the Web server received the uploaded file, it will call the PHP script specified in the form action attribute to process them. This receiving PHP script can get the uploaded file information through the predefined array called $_FILES. Uploaded file information is organized in $_FILES as a two-dimensional array as:

• $_FILES[$fieldName]['name'] - The Original file name on the browser system.
• $_FILES[$fieldName]['type'] - The file type determined by the browser.
• $_FILES[$fieldName]['size'] - The Number of bytes of the file content.
• $_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in which the uploaded file was stored on the server.
• $_FILES[$fieldName]['error'] - The error code associated with this file upload.

The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.

How can I execute a PHP script using command line?
Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument. For example, "php myScript.php", assuming "php" is the command to invoke the CLI program.
Be aware that if your PHP script was written for the Web CGI interface, it may not execute properly in command line environment.

Would I use print "$a dollars" or "{$a} dollars" to print out the amount of dollars in this example?
In this example it wouldn’t matter, since the variable is all by itself, but if you were to print something like "{$a},000,000 mln dollars", then you definitely need to use the braces.

How can we encrypt the username and password using PHP?
Answer1
You can encrypt a password with the following Mysql>SET PASSWORD=PASSWORD("Password");

Answer2
You can use the MySQL PASSWORD() function to encrypt username and password. For example,
INSERT into user (password, ...) VALUES (PASSWORD($password”)), ...);

How do you pass a variable by value?
Just like in C++, put an ampersand in front of it, like $a = &$b

What is the difference between ereg_replace() and eregi_replace()?
eregi_replace() function is identical to ereg_replace() except that it ignores case distinction when matching alphabetic characters.

When are you supposed to use endif to end the conditional statement?
When the original if was followed by : and then the code block without braces.

How can we send mail using JavaScript?
No. There is no way to send emails directly using JavaScript.

But you can use JavaScript to execute a client side email program send the email using the "mailto" code. Here is an example:

function myfunction(form)
{
tdata=document.myform.tbox1.value;
location="mailto:mailid@domain.com?subject=...";
return true;
}
How do I find out the number of parameters passed into function9. ?
func_num_args() function returns the number of parameters passed in.

Write a query for the following question
The table tbl_sites contains the following data:

---------------------------------------
Userid sitename country
---------------------------------------
1 sureshbabu indian
2 PHPprogrammer andhra
3 PHP.net usa
4 PHPtalk.com germany
5 MySQL.com usa
6 sureshbabu canada
7 PHPbuddy.com pakistan
8. PHPtalk.com austria
9. PHPfreaks.com sourthafrica
10. PHPsupport.net russia
11. sureshbabu australia
12. sureshbabu nepal
13. PHPtalk.com italy

Write a select query that will be displayed the duplicated site name and how many times it is duplicated? …
SELECT sitename, COUNT(*) AS NumOccurrences
FROM tbl_sites
GROUP BY sitename HAVING COUNT(*) > 1

Are objects passed by value or by reference?
Everything is passed by value.

How do you call a constructor for a parent class?
parent::constructor($value)

What’s the special meaning of __sleep and __wakeup?
__sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them.

Would you initialize your strings with single quotes or double quotes?
Since the data inside the single-quoted string is not parsed for variable substitution, it’s always a better idea speed-wise to initialize a string with single quotes, unless you specifically need variable substitution.
What is the difference between the functions unlink and unset?
unlink() is a function for file system handling. It will simply delete the file in context.

unset() is a function for variable management. It will make a variable undefined.

What is the difference between characters 23 and x23?
The first one is octal 23, the second is hex 23

For printing out strings, there are echo, print and printf. Explain the differences.
echo is the most primitive of them, and just outputs the contents following the construct to the screen. print is also a construct (so parentheses are optional when calling it), but it returns TRUE on successful output and FALSE if it was unable to print out the string. However, you can pass multiple parameters to echo, like:

<?php echo 'Welcome ', 'to', ' ', 'fyicenter!'; ?>

and it will output the string "Welcome to fyicenter!" print does not take multiple parameters. It is also generally argued that echo is faster, but usually the speed advantage is negligible, and might not be there for future versions of PHP. printf is a function, not a construct, and allows such advantages as formatted output, but it’s the slowest way to print out data out of echo, print and printf.

I am writing an application in PHP that outputs a printable version of driving directions. It contains some long sentences, and I am a neat freak, and would like to make sure that no line exceeds 50 characters. How do I accomplish that with PHP?
On large strings that need to be formatted according to some length specifications, use wordwrap() or chunk_split().

What’s the output of the ucwords function in this example?
$formatted = ucwords("FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS");
print $formatted;
What will be printed is FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS.
ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it’s worth using strtolower() first.

What’s the difference between htmlentities() and htmlspecialchars()?
htmlspecialchars only takes care of <, >, single quote ‘, double quote " and ampersand. htmlentities translates all occurrences of character sequences that have different meaning in HTML.

So if md5() generates the most secure hash, why would you ever use the less secure crc32() and sha1()?
Crypto usage in PHP is simple, but that doesn’t mean it’s free. First off, depending on the data that you’re encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space. Second, the more secure the crypto is, the longer is the computation time to deliver the hash value. A high volume site might be significantly slowed down, if frequent md5() generation is required.

What’s the difference between md5(), crc32() and sha1() crypto on PHP?
The major difference is the length of the hash generated. CRC32 is, evidently, 32 bits, while sha1() returns a 128 bit value, and md5() returns a 160 bit value. This is important when avoiding collisions.

What is the functionality of MD5 function in PHP?
string md5(string)

It calculates the MD5 hash of a string. The hash is a 32-character hexadecimal number.

How can we destroy the session, how can we unset the variable of a session?
session_unregister() - Unregister a global variable from the current session
session_unset() - Free all session variables

What are the other commands to know the structure of a table using MySQL commands except EXPLAIN command?
DESCRIBE table_name;

How can we find the number of rows in a table using MySQL?
Use this for MySQL

SELECT COUNT(*) FROM table_name;

How can we find the number of rows in a result set using PHP?
Here is how can you find the number of rows in a result set in PHP:

$result = mysql_query($any_valid_sql, $database_link);
$num_rows = mysql_num_rows($result);
echo "$num_rows rows found";

Give the syntax of GRANT commands?
The generic syntax for GRANT is as following

GRANT [rights] on [database] TO [username@hostname] IDENTIFIED BY [password]

Now rights can be:
a) ALL privilages
b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.

We can grant rights on all database by using *.* or some specific database by database.* or a specific table by database.table_name.

Give the syntax of REVOKE commands?
The generic syntax for revoke is as following

REVOKE [rights] on [database] FROM [username@hostname]

Now rights can be:
a) ALL privileges
b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.

We can grant rights on all database by using *.* or some specific database by database.* or a specific table by database.table_name.

What is the difference between CHAR and VARCHAR data types?
CHAR is a fixed length data type. CHAR(n) will take n characters of storage even if you enter less than n characters to that column. For example, "Hello!" will be stored as "Hello! " in CHAR(10) column.
VARCHAR is a variable length data type. VARCHAR(n) will take only the required storage for the actual number of characters entered to that column. For example, "Hello!" will be stored as "Hello!" in VARCHAR(10) column.
How can we encrypt and decrypt a data present in a mysql table using mysql?
AES_ENCRYPT() and AES_DECRYPT()

Will comparison of string "10" and integer 11 work in PHP?
Yes, internally PHP will cast everything to the integer type, so numbers 10 and 11 will be compared.

How can I load data from a text file into a table?
The MySQL provides a LOAD DATA INFILE command. You can load data from a file. Great tool but you need to make sure that:

a) Data must be delimited
b) Data fields must match table columns correctly

How can we know the number of days between two given dates using MySQL?
Use DATEDIFF()

SELECT DATEDIFF(NOW(),'2006-07-01');

How can we change the name of a column of a table?
This will change the name of column:

ALTER TABLE table_name CHANGE old_colm_name new_colm_name

How can we change the data type of a column of a table?
This will change the data type of a column:

ALTER TABLE table_name CHANGE colm_name same_colm_name [new data type]

What is the difference between GROUP BY and ORDER BY in SQL?
To sort a result, use an ORDER BY clause.
The most general way to satisfy a GROUP BY clause is to scan the whole table and create a new temporary table where all rows from each group are consecutive, and then use this temporary table to discover groups and apply aggregate functions (if any).
ORDER BY [col1],[col2],...[coln]; Tells DBMS according to what columns it should sort the result. If two rows will hawe the same value in col1 it will try to sort them according to col2 and so on.
GROUP BY [col1],[col2],...[coln]; Tells DBMS to group (aggregate) results with same value of column col1. You can use COUNT(col1), SUM(col1), AVG(col1) with it, if you want to count all items in group, sum all values or view average.
What are the differences between mysql_fetch_array(), mysql_fetch_object(), mysql_fetch_row()?
Answer 1:
mysql_fetch_array() -> Fetch a result row as a combination of associative array and regular array.
mysql_fetch_object() -> Fetch a result row as an object.
mysql_fetch_row() -> Fetch a result set as a regular array().


Answer 2:
The difference between mysql_fetch_row() and mysql_fetch_array() is that the first returns the results in a numeric array ($row[0], $row[1], etc.), while the latter returns a the results an array containing both numeric and associative keys ($row['name'], $row['email'], etc.). mysql_fetch_object() returns an object ($row->name, $row->email, etc.).

If we login more than one browser windows at the same time with same user and after that we close one window, then is the session is exist to other windows or not? And if yes then why? If no then why?
Session depends on browser. If browser is closed then session is lost. The session data will be deleted after session time out. If connection is lost and you recreate connection, then session will continue in the browser.

What are the MySQL database files stored in system ?
Data is stored in name.myd
Table structure is stored in name.frm
Index is stored in name.myi

What is the difference between PHP4 and PHP5?
PHP4 cannot support oops concepts and Zend engine 1 is used.

PHP5 supports oops concepts and Zend engine 2 is used.
Error supporting is increased in PHP5.
XML and SQLLite will is increased in PHP5.

Can we use include(abc.PHP) two times in a PHP page makeit.PHP”?
Yes we can include that many times we want, but here are some things to make sure of:
(including abc.PHP, the file names are case-sensitive)
there shouldn't be any duplicate function names, means there should not be functions or classes or variables with the same name in abc.PHP and makeit.php

How can we encrypt and decrypt a data presented in a table using MySQL?
You can use functions: AES_ENCRYPT() and AES_DECRYPT() like:

AES_ENCRYPT(str, key_str)
AES_DECRYPT(crypt_str, key_str)

How can I retrieve values from one database server and store them in other database server using PHP?
For this purpose, you can first read the data from one server into session variables. Then connect to other server and simply insert the data into the database.

WHO IS THE FATHER OF PHP AND WHAT IS THE CURRENT VERSION OF PHP AND MYSQL?
Rasmus Lerdorf.
PHP 5.1. Beta
MySQL 5.0

IN HOW MANY WAYS WE CAN RETRIEVE DATA IN THE RESULT SET OF MYSQL USING PHP?
mysql_fetch_array - Fetch a result row as an associative array, a numeric array, or both
mysql_fetch_assoc - Fetch a result row as an associative array
mysql_fetch_object - Fetch a result row as an object
mysql_fetch_row —- Get a result row as an enumerated array

What are the functions for IMAP?
imap_body - Read the message body
imap_check - Check current mailbox
imap_delete - Mark a message for deletion from current mailbox
imap_mail - Send an email message

What are encryption functions in PHP?
CRYPT()
MD5()

How can we get the properties (size, type, width, height) of an image using php image functions?
To know the image size use getimagesize() function
To know the image width use imagesx() function
To know the image height use imagesy() function
How can we increase the execution time of a php script?
By the use of void set_time_limit(int seconds)
Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini. If seconds is set to zero, no time limit is imposed.

When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

HOW CAN WE TAKE A BACKUP OF A MYSQL TABLE AND HOW CAN WE RESTORE IT?
Answer 1:
Create a full backup of your database: shell> mysqldump tab=/path/to/some/dir opt db_name
Or: shell> mysqlhotcopy db_name /path/to/some/dir

The full backup file is just a set of SQL statements, so restoring it is very easy:

shell> mysql "."Executed";


Answer 2:
To backup: BACKUP TABLE tbl_name TO /path/to/backup/directory
’ To restore: RESTORE TABLE tbl_name FROM /path/to/backup/directory


mysqldump: Dumping Table Structure and Data

Utility to dump a database or a collection of database for backup or for transferring the data to another SQL server (not necessarily a MySQL server). The dump will contain SQL statements to create the table and/or populate the table.
-t, no-create-info
Don't write table creation information (the CREATE TABLE statement).
-d, no-data
Don't write any row information for the table. This is very useful if you just want to get a dump of the structure for a table!

How to set cookies?
setcookie('variable','value','time')
;
variable - name of the cookie variable
value - value of the cookie variable
time - expiry time
Example: setcookie('Test',$i,time()+3600);

Test - cookie variable name
$i - value of the variable 'Test'
time()+3600 - denotes that the cookie will expire after an one hour

How to reset/destroy a cookie
Reset a cookie by specifying expire time in the past:
Example: setcookie('Test',$i,time()-3600); // already expired time

Reset a cookie by specifying its name only
Example: setcookie('Test');

WHAT TYPES OF IMAGES THAT PHP SUPPORTS?
Using imagetypes() function to find out what types of images are supported in your PHP engine.
imagetypes() - Returns the image types supported.
This function returns a bit-field corresponding to the image formats supported by the version of GD linked into PHP. The following bits are returned, IMG_GIF | IMG_JPG | IMG_PNG | IMG_WBMP | IMG_XPM.

Tools used for drawing ER diagrams.
Case Studio
Smart Draw

How can I know that a variable is a number or not using a JavaScript?
Answer 1:
bool is_numeric( mixed var)
Returns TRUE if var is a number or a numeric string, FALSE otherwise.

Answer 2:
Definition and Usage
The isNaN() function is used to check if a value is not a number.

Syntax
isNaN(number)

Parameter Description
number Required. The value to be tested

What is the use of friend function?
Friend functions
Sometimes a function is best shared among a number of different classes. Such functions can be declared either as member functions of one class or as global functions. In either case they can be set to be friends of other classes, by using a friend specifier in the class that is admitting them. Such functions can use all attributes of the class which names them as a friend, as if they were themselves members of that class.
A friend declaration is essentially a prototype for a member function, but instead of requiring an implementation with the name of that class attached by the double colon syntax, a global function or member function of another class provides the match.
class mylinkage
{
private:
mylinkage * prev;
mylinkage * next;

protected:
friend void set_prev(mylinkage* L, mylinkage* N);
void set_next(mylinkage* L);

public:
mylinkage * succ();
mylinkage * pred();
mylinkage();
};

void mylinkage::set_next(mylinkage* L) { next = L; }

void set_prev(mylinkage * L, mylinkage * N ) { N->prev = L; }

Friends in other classes
It is possible to specify a member function of another class as a friend as follows:
class C
{
friend int B::f1();
};
class B
{
int f1();
};

It is also possible to specify all the functions in another class as friends, by specifying the entire class as a friend.
class A
{
friend class B;
};

Friend functions allow binary operators to be defined which combine private data in a pair of objects. This is particularly powerful when using the operator overloading features of C++. We will return to it when we look at overloading.

What is the maximum size of a file that can be uploaded using PHP and how can we change this?
You can change maximum size of a file set upload_max_filesize variable in php.ini file

What are the advantages of stored procedures, triggers, indexes?
A stored procedure is a set of SQL commands that can be compiled and stored in the server. Once this has been done, clients don't need to keep re-issuing the entire query but can refer to the stored procedure. This provides better overall performance because the query has to be parsed only once, and less information needs to be sent between the server and the client. You can also raise the conceptual level by having libraries of functions in the server. However, stored procedures of course do increase the load on the database server system, as more of the work is done on the server side and less on the client (application) side. Triggers will also be implemented. A trigger is effectively a type of stored procedure, one that is invoked when a particular event occurs. For example, you can install a stored procedure that is triggered each time a record is deleted from a transaction table and that stored procedure automatically deletes the corresponding customer from a customer table when all his transactions are deleted. Indexes are used to find rows with specific column values quickly. Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant rows. The larger the table, the more this costs. If the table has an index for the columns in question, MySQL can quickly determine the position to seek to in the middle of the data file without having to look at all the data. If a table has 1,000 rows, this is at least 100 times faster than reading sequentially. If you need to access most of the rows, it is faster to read sequentially, because this minimizes disk seeks.

What’s the difference between accessing a class method via -> and via ::?
:: is allowed to access methods that can perform static operations, i.e. those, which do not require object initialization.

How can increase the performance of MySQL select query?
We can use LIMIT to stop MySql for further search in table after we have received our required no. of records, also we can use LEFT JOIN or RIGHT JOIN instead of full join in cases we have related data in two or more tables.

What are the different ways to login to a remote server? Explain the means, advantages and disadvantages?
There is at least 3 ways to logon to a remote server:
Use ssh or telnet if you concern with security
You can also use rlogin to logon to a remote server.

How many ways we can give the output to a browser?
HTML output
PHP, ASP, JSP, Servlet Function
Script Language output Function
Different Type of embedded Package to output to a browser

What changes I have to do in php.ini file for file uploading?
Make the following line uncomment like:
; Whether to allow HTTP file uploads.
file_uploads = On
; Temporary directory for HTTP uploaded files (will use system default if not
; specified).
upload_tmp_dir = C:apache2triadtemp
; Maximum allowed size for uploaded files.
upload_max_filesize = 2M

How can I set a cron and how can I execute it in Unix, Linux, and windows?
Cron is very simply a Linux module that allows you to run commands at predetermined times or intervals. In Windows, it's called Scheduled Tasks. The name Cron is in fact derived from the same word from which we get the word chronology, which means order of time.
The easiest way to use crontab is via the crontab command.

# crontab

This command 'edits' the crontab. Upon employing this command, you will be able to enter the commands that you wish to run. My version of
Linux uses the text editor vi. You can find information on using vi here.

The syntax of this file is very important – if you get it wrong, your crontab will not function properly. The syntax of the file should be as follows:
minutes hours day_of_month month day_of_week command

All the variables, with the exception of the command itself, are numerical constants. In addition to an asterisk (*), which is a wildcard that allows any value, the ranges permitted for each field are as follows:

Minutes: 0-59
Hours: 0-23
Day_of_month: 1-31
Month: 1-12
Weekday: 0-6

We can also include multiple values for each entry, simply by separating each value with a comma.
command can be any shell command and, as we will see momentarily, can also be used to execute a Web document such as a PHP file.
So, if we want to run a script every Tuesday morning at 8:15 AM, our mycronjob file will contain the following content on a single line:

15 8 * * 2 /path/to/scriptname

This all seems simple enough, right? Not so fast! If you try to run a PHP script in this manner, nothing will happen (barring very special configurations that have PHP compiled as an executable, as opposed to an Apache module). The reason is that, in order for PHP to be parsed, it needs to be passed through Apache. In other words, the page needs to be called via a browser or other means of retrieving

Web content. For our purposes, I'll assume that your server configuration includes wget, as is the case with most default configurations. To test your configuration, log in to shell. If you're using an RPM-based system (e.g. Redhat or Mandrake), type the following:

# wget help

If you are greeted with a wget package identification, it is installed in your system.
You could execute the PHP by invoking wget on the URL to the page, like so:

# wget http://www.example.com/file.php

Now, let's go back to the mailstock.php file we created in the first part of this article. We saved it in our document root, so it should be accessible via the Internet. Remember that we wanted it to run at 4PM Eastern time, and send you your precious closing bell report? Since I'm located in the Eastern timezone, we can go ahead and set up our crontab to use 4:00, but if you live elsewhere, you might have to compensate for the time difference when setting this value.
This is what my crontab will look like:

0 4 * * 1,2,3,4,5 wget http://www.example.com/mailstock.php

How many ways I can redirect a PHP page?
Here are the possible ways of php page redirection.

1. Using Java script:
'; echo 'window.location.href="'.$filename.'";'; echo ''; echo ''; echo ''; echo ''; } } redirect('http://maosjb.com'); ?>

2. Using php function: header("Location:http://maosjb.com ");

What type of headers have to be added in the mail function to attach a file?
$boundary = '--' . md5( uniqid ( rand() ) );
$headers = "From: "Me"n";
$headers .= "MIME-Version: 1.0n";
$headers .= "Content-Type: multipart/mixed; boundary="$boundary"";

How can I embed a java programme in php file and what changes have to be done in php.ini file?
There are two possible ways to bridge PHP and Java: you can either integrate PHP into a Java Servlet environment, which is the more stable and efficient solution, or integrate Java support into PHP. The former is provided by a SAPI module that interfaces with the Servlet server, the latter by this Java extension.
The Java extension provides a simple and effective means for creating and invoking methods on Java objects from PHP. The JVM is created using JNI, and everything runs in-process.

Example Code:

getProperty('java.version') . ''; echo 'Java vendor=' . $system->getProperty('java.vendor') . ''; echo 'OS=' . $system->getProperty('os.name') . ' ' . $system->getProperty('os.version') . ' on ' . $system->getProperty('os.arch') . ' '; // java.util.Date example $formatter = new Java('java.text.SimpleDateFormat', "EEEE, MMMM dd, yyyy 'at' h:mm:ss a zzzz"); echo $formatter->format(new Java('java.util.Date')); ?>

The behaviour of these functions is affected by settings in php.ini.
Table 1. Java configuration options
Name
Default
Changeable
java.class.path
NULL
PHP_INI_ALL
Name Default Changeable
java.home
NULL
PHP_INI_ALL
java.library.path
NULL
PHP_INI_ALL
java.library
JAVALIB
PHP_INI_ALL

How To Turn On the Session Support?
The session support can be turned on automatically at the site level, or manually in each PHP page script:

• Turning on session support automatically at the site level: Set session.auto_start = 1 in php.ini.
• Turning on session support manually in each page script: Call session_start() funtion.

Explain the ternary conditional operator in PHP?
Expression preceding the ? is evaluated, if it’s true, then the expression preceding the : is executed, otherwise, the expression following : is executed.

How To Read the Entire File into a Single String?
If you have a file, and you want to read the entire file into a single string, you can use the file_get_contents() function. It opens the specified file, reads all characters in the file, and returns them in a single string. Here is a PHP script example on how to file_get_contents():

<?php
$file = file_get_contents("/windows/system32/drivers/etc/services");
print("Size of the file: ".strlen($file)."n");
?>

This script will print:
Size of the file: 7116