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15 questions to solve
Instructions
- This quiz goes to full-screen once you press the Start button.
- At the end of the quiz, you are able to review all the questions that you answered wrong and see their explanations.
What's the problem in the code below?
<?php
echo 'Hello World!';There is absolutely no problem in the given code — it's perfectly fine. Hence, the correct choice is (D).
$1str is a valid variable name in PHP. Yes or no?$1str is not a valid name for a variable because it has a digit at its beginning. Refer to PHP Variables for more information.Which of the following denotes a comment in PHP?
There are three ways to denote a comment in PHP: using
//, # and /* */. Hence, the correct choice is (D).Variable names in PHP are case-sensitive. True or false?
That's completely true — variable names are case-sensitive in PHP. That is,
$greeting is different than $GREETING and $Greeting. Refer to PHP Variables for more information.A unary operator takes how many operands?
The term 'unary' stands for 'one' and that means that a unary operator takes one operand. Hence, the correct choice is (A). Refer to PHP Operations for more information.
What does the following code output?
<?php
$x = true;
$y = false;
var_dump($x && $y);
var_dump($x || $y);The
&& operator is the logical AND operator whereas || is the logical OR operator. && evaluates to true if both its operands are true, or else to false. Similarly, || evaluates to true if either of its operands is true, or else to false. Hence, the correct choice is (C). Refer to PHP Operations for more information.What does the following code output?
<?php
$x = 50;
if ($x % 2 === 0) {
echo '2', "\n";
}
elseif ($x % 10 === 0) {
echo '10', "\n";
}The condition in the first
if statement, i.e. $x % 2 === 0, is met, and likewise, the first if statement executes. Since the next statement is an elseif, and not a standalone if statement, it's skipped because the preceding if has already been executed. Hence, 2 is printed and this goes with choice (B). Refer to PHP Control Flow for more information.In the code below, what is
(int) called?<?php
$x = (int) '10';
echo $x;(int) is referred to as a typecast and serves to convert a given value into an integer. Refer to PHP Data Types for more information.Which of the following is a function to get the type of a given value?
gettype() is used to return the type of a given value in PHP. Hence, the correct choice is (C). Refer to PHP Data Types for more information.What does the following code output?
<?php
$nums = [1, 3, 4, 10];
for ($i = 0; $i < count($nums) - 1; $i++) {
echo $nums[$i];
}The condition
$i < count($nums) - 1 causes the loop to iterate from the first element of $nums to the second last element. Moreover, echo $nums[i] prints each of the numbers one after another, without leaving a blank line or space between them. This results in the output 134. Hence, the correct choice is (C). Refer to PHP Control Flow for more information.What does
10++ return?The increment operator, or in general any assignment-related operator, can only be used with variables (or other identifiers).
10 is a literal, not a variable, and thus it's illegal to use the increment operator with it. Hence, the correct choice is (C). Refer to PHP Operations for more information.What's the problem in the code below?
<?php
do
echo 'Please enter 0 > ';
$input = rtrim(fgets(STDIN));
while ($input !== '0');
echo "You entered '0'";The problem is that the body of
do...while from line 4 to 5 is not encapsulated in a pair of curly braces ({}). The curly braces denotes a block statement in PHP and since only a single statement is expected after do, we need to use a block statement after do and then put all the respective statements inside the block. Refer to PHP Control Flow for more information.In the code below, what is
$a called?<?php
function add($a, $b) {
return $a + $b;
}$a is a parameter of the function add(). Hence, the correct choice is (C). Refer to PHP Functions for more information.What does the following code output?
<?php
function add($a, $b) {
$a + $b;
}
var_dump(add(10, 20));When a function doesn't have an explicit
return statement, PHP automatically returns NULL. Likewise, in the code above add(10, 20) returns NULL and then var_dump(NULL) prints NULL. Hence, the correct choice is (C). Refer to PHP Functions for more information.In the code below, what is the scope of the variable
$a?<?php
$a = 10;
echo $a;A variable defined outside all exisiting function definitions is a global variable in PHP i.e. it has a global scope. Hence, the correct choice is (A). Refer to PHP Scoping for more information.
