Why variables are needed in PHP - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable in PHP.

PHP

<?php
$[1] = 10;
echo $number;
?>

Drag options to blanks, or click blank then click option'

Anumber

B10

Cecho

Dvar

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number as a variable name

Forgetting the dollar sign before the variable name

Using reserved words like 'var' as variable names

In PHP, variables start with a dollar sign followed by the variable name. Here, $number is the variable name.

2fill in blank

medium

Complete the code to output the value of the variable.

PHP

<?php
$age = 25;
echo [1];
?>

Drag options to blanks, or click blank then click option'

Aecho

B$25

C$age

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the dollar sign when echoing the variable

Trying to echo the variable name as a string without the dollar sign

To output the value of a variable in PHP, you use echo followed by the variable name with a dollar sign.

3fill in blank

hard

Fix the error in the code by completing the variable assignment.

PHP

<?php
$[1] = 'Hello World';
echo $greeting;
?>

Drag options to blanks, or click blank then click option'

Aworld

Bmessage

CHello

Dgreeting

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in assignment and output

Forgetting the dollar sign in variable names

The variable name used in the assignment must match the one used in echo. Here, $greeting is correct.

4fill in blank

hard

Fill both blanks to create and output a variable holding a string.

PHP

<?php
$[1] = [2];
echo $name;
?>

Drag options to blanks, or click blank then click option'

Aname

B"John"

CJohn

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around string values

Using a variable name that doesn't match the echo statement

The variable $name is assigned the string value "John". Strings must be in quotes in PHP.

5fill in blank

hard

Fill all three blanks to declare, assign, and output a variable with a number.

PHP

<?php
$[1] = [2];
echo $[3];
?>

Drag options to blanks, or click blank then click option'

Ascore

B100

Dpoints

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in assignment and echo

Putting quotes around numbers

The variable $score is assigned the number 100 and then output with echo. The variable name must be consistent.

Practice

1. Why do we need variables in PHP?

easy

A. To create new functions automatically

B. To make the program run faster

C. To store and reuse data easily throughout the program

D. To change the PHP version

Solution

1. Step 1: Understand the role of variables

   Variables hold data that can be used and changed later in the program.

2. Step 2: Identify why this is useful

   Storing data in variables allows easy reuse and modification without rewriting values.

3. Final Answer:

   To store and reuse data easily throughout the program -> Option C

4. Quick Check:

   Variables store data for reuse [OK]

Hint: Variables hold data to use later in code [OK]

Common Mistakes:

• Thinking variables speed up the program
• Confusing variables with functions
• Believing variables change PHP version

2. Which of the following is the correct way to declare a variable in PHP?

easy

A. name = "John";

B. $name = "John";

C. var name = "John";

D. let $name = "John";

Solution

1. Step 1: Recall PHP variable syntax

   In PHP, variables start with a dollar sign ($) followed by the name.

2. Step 2: Check each option

   Only $name = "John"; uses $ before the variable name and assigns a string correctly.

3. Final Answer:

   $name = "John"; -> Option B

4. Quick Check:

   PHP variables start with $ [OK]

Hint: PHP variables always start with $ [OK]

Common Mistakes:

• Omitting the $ sign before variable name
• Using JavaScript syntax like var or let
• Assigning without semicolon

3. What will be the output of this PHP code?

$age = 25;
$age = $age + 5;
echo $age;

medium

A. 25

B. Error

C. 5

D. 30

Solution

1. Step 1: Understand variable assignment and update

   $age starts at 25, then 5 is added and stored back in $age.

2. Step 2: Calculate the new value

   25 + 5 = 30, so $age becomes 30.

3. Final Answer:

   30 -> Option D

4. Quick Check:

   25 + 5 = 30 [OK]

Hint: Adding to variable updates its value [OK]

Common Mistakes:

• Expecting original value without addition
• Confusing assignment with comparison
• Thinking echo prints variable name

4. Find the error in this PHP code:

$count = 10
echo $count;

medium

A. Missing semicolon after variable assignment

B. Variable name should not start with $

C. echo cannot print variables

D. Variable must be declared with var keyword

Solution

1. Step 1: Check syntax rules for PHP statements

   Each statement must end with a semicolon (;).

2. Step 2: Identify missing semicolon

   The first line lacks a semicolon after 10, causing a syntax error.

3. Final Answer:

   Missing semicolon after variable assignment -> Option A

4. Quick Check:

   Statements need ; at end [OK]

Hint: Always end PHP statements with ; [OK]

Common Mistakes:

• Forgetting semicolon at line end
• Thinking $ is not needed for variables
• Believing echo can't print variables

5. You want to store a user's first name and last name separately, then combine them into a full name variable. Which PHP code correctly does this?

hard

A. $first = "Anna"; $last = "Lee"; $full = $first . " " . $last; echo $full;

B. $first = "Anna"; $last = "Lee"; $full = $first + " " + $last; echo $full;

C. $first = "Anna"; $last = "Lee"; $full = '$first $last'; echo $full;

D. $first = "Anna"; $last = "Lee"; $full = $first & " " & $last; echo $full;

Solution

1. Step 1: Understand string concatenation in PHP

   PHP uses the dot (.) operator to join strings.

2. Step 2: Check each option for correct concatenation

   $first = "Anna"; $last = "Lee"; $full = $first . " " . $last; echo $full; uses . to join first name, space, and last name correctly.

3. Final Answer:

   $first = "Anna"; $last = "Lee"; $full = $first . " " . $last; echo $full; -> Option A

4. Quick Check:

   Use . to join strings in PHP [OK]

Hint: Use . to join strings in PHP [OK]

Common Mistakes:

• Using + or & instead of . for strings
• Forgetting spaces between names
• Trying to combine variables without concatenation