$_GET for URL parameters in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code using $_GET?

Consider the URL: http://example.com/page.php?name=Alice&age=30. What will this PHP code output?

PHP

<?php
$name = $_GET['name'];
$age = $_GET['age'];
echo "Name: $name, Age: $age";
?>

A Name: , Age: 30

B Name: Alice, Age: 30

C Name: Alice, Age:

D Name: , Age:

💡 Hint

Check how $_GET accesses URL parameters by their keys.

The $_GET superglobal array contains URL parameters as key-value pairs. Accessing $_GET['name'] returns 'Alice' and $_GET['age'] returns '30'.

🧠 Conceptual

intermediate

What happens if a URL parameter is missing in $_GET?

Given the URL http://example.com/page.php?user=Bob, what will be the output of this code?

PHP

<?php
$user = $_GET['user'];
$age = $_GET['age'];
echo "User: $user, Age: $age";
?>

A User: Bob, Age: 0

B User: Bob, Age: NULL

C User: Bob, Age:

D User: Bob, Age: Notice: Undefined index: age

💡 Hint

Accessing a missing key in $_GET causes a notice error.

Trying to access $_GET['age'] when 'age' is not in the URL causes a PHP Notice: Undefined index error.

🔧 Debug

advanced

Why does this PHP code not output the expected $_GET value?

URL: http://example.com/page.php?city=Paris Code:

<?php
$city = $_GET[city];
echo "City: $city";
?>

What is the problem?

A Missing quotes around 'city' key causes a PHP notice or error.

B The $_GET array is empty because URL parameters are not passed.

C The variable $city is overwritten before echo.

D The echo statement syntax is incorrect.

💡 Hint

Array keys must be quoted strings in PHP.

In PHP, array keys must be quoted strings. Using $_GET[city] without quotes causes PHP to look for a constant named city, which is undefined and triggers a notice.

❓ Predict Output

advanced

What is the output of this PHP code with multiple $_GET parameters?

URL: http://example.com/page.php?item=book&price=15&discount=5 Code:

<?php
$item = $_GET['item'];
$price = $_GET['price'];
$discount = $_GET['discount'];
$total = $price - $discount;
echo "Item: $item, Total Price: $total";
?>

A Item: book, Total Price: 20

B Item: book, Total Price: 15-5

C Item: book, Total Price: 10

D Item: book, Total Price: 0

💡 Hint

URL parameters are strings; PHP converts them to numbers in arithmetic.

PHP converts string numbers to integers automatically in arithmetic operations. 15 - 5 equals 10.

📝 Syntax

expert

Which option causes a syntax error when accessing $_GET parameters?

Identify the code snippet that will cause a PHP syntax error.

A $value = $_GET['key']

B $value = $_GET[key];

C $value = $_GET["key"];

D $value = $_GET['key'];

💡 Hint

Check for missing semicolons in PHP statements.

Option A is missing the semicolon at the end of the statement, causing a syntax error.