Printf and sprintf formatting in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code using printf?

Consider the following PHP code snippet. What will it print?

PHP

<?php
$number = 123.456;
printf("%.2f\n", $number);
?>

A 123.46

B 123

C 123.456

D 123.45

💡 Hint

Look at the format specifier %.2f which controls decimal places.

The format %.2f rounds the number to 2 decimal places, so 123.456 becomes 123.46.

❓ Predict Output

intermediate

What does this sprintf return?

What string does this PHP code return?

PHP

<?php
$result = sprintf("%05d", 42);
echo $result;
?>

A 42

B 43

C 00042

D 41

💡 Hint

The format %05d pads the number with zeros to width 5.

The %05d means print an integer padded with zeros to 5 characters, so 42 becomes '00042'.

❓ Predict Output

advanced

What is the output of this complex printf?

What will this PHP code print?

PHP

<?php
$val = 255;
printf("%#08x\n", $val);
?>

A 0x000000ff

B 0x0000ff00

C 0x0000ff

D ff0000x0

💡 Hint

The %#08x format prints hex with 0x prefix and pads to 8 characters.

The %#08x prints the number in hex with 0x prefix and pads with zeros to 8 characters total, so 255 (0xff) becomes '0x000000ff'.

❓ Predict Output

advanced

What error or output does this code produce?

What happens when this PHP code runs?

PHP

<?php
printf("%d %s", 10);
?>

A 10

B Warning: printf(): Too few arguments

C 10 %s

D 10 0

💡 Hint

Check if the number of arguments matches the format specifiers.

The format string expects two arguments (%d and %s), but only one (10) is given, so PHP raises a warning about too few arguments.

🧠 Conceptual

expert

How many characters does this sprintf string have?

What is the length of the string returned by this PHP code?

PHP

<?php
$str = sprintf("%-10s%04d", "Hi", 7);
echo strlen($str);
?>

A 13

B 12

C 10

D 14

💡 Hint

Consider the width specifiers: %-10s and %04d.

The %-10s prints 'Hi' left-aligned in 10 spaces (adds 8 spaces), and %04d prints 7 padded with zeros to 4 digits ('0007'). Total length is 10 + 4 = 14 characters.