PHP Interview Questions and answers pdf free download

You can download latest PHP Interview Questions & answers pdf 2015 from here....

What does a special set of tags <?= and ?> do in PHP?

– The output is displayed directly to the browser.
What’s the difference between include and require?
- 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.

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

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

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 do you define a constant?

- Via define() directive, like define ("MYCONSTANT", 100);
How do you pass a variable by value?
- Just like in C++, put an ampersand in front of it, like $a = &$b
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.

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.

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 do I find out the number of parameters passed into function?

- func_num_args() function returns the number of parameters passed in.

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

- 100, it’s a reference to existing variable.

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.

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.

Why doesn’t the following code print the newline properly? <?php

$str = ‘Hello, there.nHow are you?nThanks for visiting TechInterviews’;
print $str;
?>
Because inside the single quotes the n character is not interpreted as newline, just as a sequence of two characters - and n.

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.