Question 1

I am trying to assign a variable the value of 0123, but it keeps coming up with a different number, what’s the problem?

Accepted Answer

PHP Interpreter treats numbers beginning with 0 as octal Look at the similar PHP interview questions for more numeric problems

Question 2

If the variable $a is equal to 5 and variable $b is equal to character a, what’s the value of $$b?

Accepted Answer

100, it’s a reference to existing variable

Question 3

What’s the special meaning of __sleep and __wakeup?

Accepted Answer

__sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them

Question 4

What is the difference between characters 23 and x23?

Accepted Answer

The first one is octal 23, the second is hex 23

Question 5

What’s the difference between md5( ), crc32( ) and sha1( ) crypto on PHP?

Accepted Answer

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

Question 6

What’s the difference between include and require?

Accepted Answer

It’s how they handle failures If the file is not found by require(), it will cause a fatal error and halt the execution of the script If the file is not found by include(), a warning will be issued, but execution will continue

Question 7

How do you define a constant?

Accepted Answer

Via define() directive, like define ("MYCONSTANT", 100);

Question 8

How do you pass a variable by value?

Accepted Answer

Just like in C++, put an ampersand in front of it, like $a = &$b

Question 9

Explain the ternary conditional operator in PHP?

Accepted Answer

Expression preceding the ? is evaluated, if it’s true, then the expression preceding the : is executed, otherwise, the expression following : is executed

Question 10

Are objects passed by value or by reference?

Accepted Answer

Everything is passed by value

Question 11

How do you call a constructor for a parent class?

Accepted Answer

parent::constructor($value)

Question 12

Would you initialize your strings with single quotes or double quotes?

Accepted Answer

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

Question 13

For printing out strings, there are echo, print and printf. Explain the differences.

Accepted Answer

- 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: and it will output the string "Welcome to TechInterviews!" 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

Question 14

What’s the difference between htmlentities( ) and htmlspecialchars( )?

Accepted Answer

htmlspecialchars only takes care of , single quote ‘, double quote " and ampersand htmlentities translates all occurrences of character sequences that have different meaning in HTML

Question 15

Why we use array_flip

Accepted Answer

array_flip exchange the keys with their associated values in array ie Keys becomes values and values becomes keys "php","course2"=>"html"); $new_array = array_flip($arrayName); print_r($new_array); ?> OUTPUT : Array ( [php] => course1 [html] => course2 )

Question 16

What is a .htacces file

Accepted Answer

htaccess is a configuration file running on Apache serverThese htaccess file used to change the functionality and features of apache web server eg htaccess file used for url rewrite htaccess file used to make the site password protected htaccess file can restrict some ip addresses ,so that on restricted ip adresses site will not open

Question 17

Can we use include ("xyz.PHP") two times in a PHP page "index.PHP"?

Accepted Answer

Yes we can use include("xyzphp") more than one time in any page but it create a prob when xyzphp file contain some funtions declaration then error will come for already declared function in this file else not a prob like if you want to show same content two time in page then must incude it two time not a prob

Question 18

How can we get the browser properties using PHP?

Accepted Answer

By using $_SERVER['HTTP_USER_AGENT'] variable

Question 19

What is the maximum size of a file that can be uploaded using PHP and how can we change this?

Accepted Answer

By default the maximum size is 2MB and we can change the following setup at phpiniupload_max_filesize = 2M

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