Infinite loop prevention in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an infinite loop?

An infinite loop is a loop that never stops running because its exit condition is never met.

beginner

How can you prevent an infinite loop in Python?

Make sure the loop's condition will eventually become false by updating variables inside the loop.

beginner

What role does a loop counter play in preventing infinite loops?

A loop counter tracks how many times the loop runs and can be used to stop the loop after a set number of iterations.

intermediate

Why is it important to test loops with different inputs?

Testing with different inputs helps ensure the loop stops correctly and does not run forever.

intermediate

What is a common debugging method to find infinite loops?

Adding print statements inside the loop to see how variables change and if the exit condition is reached.

What happens if a loop's exit condition is never met?

A The loop skips all iterations.

B The loop runs once.

C The program crashes immediately.

D The loop runs forever (infinite loop).

If the exit condition is never met, the loop keeps running endlessly, causing an infinite loop.

Which of these helps prevent infinite loops?

A Using only while True without breaks.

B Leaving the loop condition unchanged.

C Updating loop variables inside the loop.

D Ignoring loop counters.

Updating loop variables ensures the exit condition can eventually be met, stopping the loop.

What is a loop counter used for?

A To count how many times the loop runs.

B To make the loop run infinitely.

C To skip loop iterations.

D To crash the program.

A loop counter tracks iterations and can help stop the loop after a set number.

Which debugging method helps find infinite loops?

A Adding print statements inside the loop.

B Removing all loop conditions.

C Ignoring variable changes.

D Running the program without testing.

Print statements show variable changes and help check if the loop will stop.

What is a safe way to write a while loop to avoid infinite loops?

A Use while True without any break.

B Ensure the condition will become false by changing variables inside the loop.

C Never update variables inside the loop.

D Write loops without conditions.

Changing variables inside the loop helps the condition become false and stops the loop.

Explain what causes an infinite loop and how you can prevent it in Python.

Think about what makes a loop stop running.

Describe how you would debug a program that seems stuck in an infinite loop.

How can you see what the program is doing inside the loop?