While loop execution model in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a while loop in PHP?

A while loop in PHP repeats a block of code as long as a given condition is true. It checks the condition before each iteration.

beginner

When does the while loop stop executing?

The while loop stops when the condition becomes false. It does not run the loop body if the condition is false at the start.

intermediate

What happens if the while loop condition is always true?

If the condition is always true, the while loop runs forever, causing an infinite loop unless stopped manually or by a break statement.

beginner

Explain the execution order of a while loop.

First, the condition is checked. If true, the loop body runs. Then the condition is checked again. This repeats until the condition is false.

intermediate

How can you safely avoid infinite loops with while?

Make sure the loop condition will eventually become false by changing variables inside the loop. Also, use break statements if needed.

What does a while loop check before running its code block?

A The loop body

B The loop condition

C The loop counter after running

D Nothing, it runs once automatically

A while loop checks the condition before each iteration to decide if it should run the loop body.

What happens if the while loop condition is false at the start?

A The loop never runs

B The loop runs once

C The loop runs twice

D The loop runs infinitely

If the condition is false initially, the while loop does not run at all.

Which of these can cause an infinite while loop?

A Condition changes to false inside loop

B Condition always false

C Condition always true

D Using break inside loop

If the condition never becomes false, the loop runs forever, causing an infinite loop.

How do you stop a while loop manually inside the loop?

A Using <code>return</code>

B Using <code>continue</code>

C Using <code>exit</code>

D Using <code>break</code>

The break statement immediately stops the loop execution.

What is the main difference between while and do-while loops?

A <code>while</code> checks condition before loop, <code>do-while</code> after

B <code>while</code> runs once, <code>do-while</code> never runs

C <code>while</code> loops forever, <code>do-while</code> does not

D No difference

while checks condition first, so may not run; do-while runs loop body once before checking.

Describe how a while loop works in PHP from start to finish.

Think about what happens before and after running the code inside the loop.

Explain how to prevent infinite loops when using a while loop.

Consider what makes the loop stop running.