Return values in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP function call?

Consider the following PHP code. What will be printed when foo() is called?

PHP

<?php
function foo() {
    return 5 + 3;
}
echo foo();

A Error: Undefined function foo

B 53

C 8

D 5 + 3

💡 Hint

Remember that return sends a value back from the function.

The function foo() returns the sum of 5 and 3, which is 8. The echo prints this returned value.

❓ Predict Output

intermediate

What does this function return?

Look at this PHP function. What value does it return when called with bar(4)?

PHP

<?php
function bar($x) {
    if ($x > 5) {
        return $x * 2;
    }
    return $x + 2;
}
$result = bar(4);
echo $result;

A 10

B 8

C Error: Missing return statement

D 6

💡 Hint

Check which return line runs for the input 4.

Since 4 is not greater than 5, the function returns 4 + 2 = 6.

🔧 Debug

advanced

What error does this code produce?

Examine this PHP code. What error will it cause when run?

PHP

<?php
function baz() {
    echo "Hello";
}
$result = baz();
echo $result;

A Warning: Trying to echo non-scalar value

B No error, outputs 'Hello'

C Notice: Trying to echo null value

D Notice: Undefined variable $result

💡 Hint

Consider what the function baz() returns by default.

The function baz() echoes "Hello" but does not have a return statement, so it returns null. echo $result; (null) outputs nothing and produces no error. The output is 'Hello'.

❓ Predict Output

advanced

What is the output of this recursive function?

What will this PHP code print?

PHP

<?php
function countdown($n) {
    if ($n <= 0) {
        return "Done!";
    }
    return $n . " " . countdown($n - 1);
}
echo countdown(3);

A 3 2 1 Done!

B 3 2 1

C Done! 1 2 3

D 3 2 1 0 Done!

💡 Hint

Trace the function calls and how the strings join.

The function returns a string counting down from 3 to 1, then adds 'Done!'. So the output is '3 2 1 Done!'.

🧠 Conceptual

expert

What is the value of $result after this code runs?

Consider this PHP code snippet. What is the value of $result after execution?

PHP

<?php
function test() {
    return;
    return 10;
}
$result = test();

A null

B Error: unreachable code

C 0

D 10

💡 Hint

What happens when a function returns without a value?

The first return; exits the function immediately returning null. The second return 10; is never reached.