PHP Interview Questions and Answers

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

The output is displayed directly to the browser.

2.   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.

3.   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.

4.   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.

5.   How do you define a constant?

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

6.   How do you pass a variable by value?

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

7.   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.

8.   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.

9.   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.

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

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