Why output functions matter in PHP - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of echo vs print

What is the output of the following PHP code?

PHP

<?php
echo 'Hello';
print ' World!';
?>

A Error: Cannot use echo and print together

B HelloWorld!

C Hello\nWorld!

D Hello World!

💡 Hint

Both echo and print output strings directly.

Both echo and print output their strings directly without adding spaces or newlines. So the output is 'Hello World!'.

🧠 Conceptual

intermediate

Why use output buffering?

Why is output buffering useful in PHP?

A It disables all output functions

B It allows capturing output before sending it to the browser

C It speeds up the PHP interpreter

D It automatically formats output as JSON

💡 Hint

Think about controlling when output is sent.

Output buffering lets you collect output in memory first, so you can modify or delay sending it to the browser.

🔧 Debug

advanced

Why does this code produce no output?

What is the reason this PHP code produces no output?

PHP

<?php
ob_start();
echo 'Test';
// missing ob_end_flush();
?>

A Output is buffered but never flushed to the browser

B echo is disabled inside ob_start()

C Output buffering automatically discards output

D Syntax error due to missing semicolon

💡 Hint

Check what happens to buffered output if not flushed.

The output is stored in the buffer but never sent because ob_end_flush() or ob_flush() is not called.

📝 Syntax

advanced

Identify the syntax error in output code

Which option contains a syntax error in PHP output code?

PHP

<?php
print('Hello World!');
echo 'Goodbye';
?>

A <?php echo 'Hello World!' ?>

B <?php echo 'Hello World!'; ?>

C <?php echo('Hello World!'); ?>

D <?php print 'Hello World!'; ?>

💡 Hint

Check semicolon placement carefully.

Option A has a semicolon after the PHP closing tag, which is invalid syntax.

🚀 Application

expert

How many items are in the output array?

What is the number of elements in the array returned by this PHP code?

PHP

<?php
ob_start();
echo 'A';
echo 'B';
$output = ob_get_contents();
ob_end_clean();
$result = str_split($output);
return $result;
?>

A 1

B 0

C 2

D 3

💡 Hint

Count characters echoed before capturing output.

The output buffer contains 'AB', so str_split creates an array with 2 elements: 'A' and 'B'.