For loop execution model in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple for loop with break

What is the output of this PHP code?

PHP

<?php
for ($i = 0; $i < 5; $i++) {
    if ($i == 3) {
        break;
    }
    echo $i . ' ';
}
?>

A 0 1 2

B 0 1 2 3

C 0 1 2 3 4

D 1 2 3

💡 Hint

The loop stops when the condition inside the if is true.

The loop starts at 0 and prints each number. When i equals 3, the break stops the loop before printing 3.

❓ Predict Output

intermediate

For loop with continue statement

What will this PHP code output?

PHP

<?php
for ($i = 0; $i < 5; $i++) {
    if ($i % 2 == 0) {
        continue;
    }
    echo $i . ' ';
}
?>

A 1 3

B 0 2 4

C 1 3 5

D 0 1 2 3 4

💡 Hint

The continue skips the current loop iteration when the number is even.

The loop prints only odd numbers because it skips even numbers using continue.

❓ Predict Output

advanced

For loop with multiple expressions in control

What is the output of this PHP code?

PHP

<?php
for ($i = 0, $j = 5; $i < 3; $i++, $j--) {
    echo $i . '-' . $j . ' ';
}
?>

A 0-5 1-4

B 0-5 1-4 2-3 3-2

C 0-5 1-4 2-3

D 5-0 4-1 3-2

💡 Hint

Both variables change each loop iteration.

The loop runs 3 times. Each time, i increases and j decreases, printing pairs.

❓ Predict Output

advanced

For loop with missing increment expression

What will this PHP code output?

PHP

<?php
for ($i = 0; $i < 3;) {
    echo $i . ' ';
    $i++;
}
?>

A 0 1 2 3

B 0 1 2

C Infinite loop (no output ends)

D Syntax error

💡 Hint

Increment can be inside the loop body.

The loop increments i inside the body, so it prints 0,1,2 and stops.

🧠 Conceptual

expert

Understanding for loop execution order

In PHP, what is the correct order of execution for the parts of a for loop?

A 3,1,2,4

B 2,1,3,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

Initialization happens once, then condition is checked before each loop.

First, initialization runs once. Then condition is checked before each iteration. If true, loop body runs, then increment runs, then condition checked again.