While loop in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a while loop in Ruby?

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

beginner

How do you write a simple while loop in Ruby that counts from 1 to 5?

You can write:<br>

i = 1
while i <= 5
  puts i
  i += 1
end

<br>This prints numbers 1 to 5.

intermediate

What happens if the condition in a while loop is never false?

The loop runs forever, causing an infinite loop. This can freeze your program unless you stop it manually.

beginner

Can you use a while loop with a condition that changes inside the loop? Give an example.

Yes. For example:<br>

count = 3
while count > 0
  puts count
  count -= 1
end

<br>The condition changes as count decreases.

intermediate

What is the difference between a while loop and an until loop in Ruby?

A while loop runs while the condition is true.<br>An until loop runs until the condition becomes true (runs while condition is false).

What does a while loop do in Ruby?

A Repeats code while a condition is true

B Repeats code once regardless of condition

C Runs code only if condition is false

D Stops code execution immediately

A while loop repeats the code block as long as the condition remains true.

What will this code print?<br>

i = 1
while i < 3
  puts i
  i += 1
end

A 1 2

B 1 2 3

C 2 3

D 3

The loop runs while i is less than 3, so it prints 1 and 2.

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

A The loop runs forever

B The loop does not run at all

C The loop runs once

D The loop runs twice

If the condition is false initially, the while loop does not run even once.

Which of these can cause an infinite while loop?

A Incrementing a variable inside the loop

B Condition is false initially

C Condition never becomes false

D Using break inside the loop

If the condition never becomes false, the loop never stops and runs forever.

How do you stop a while loop early in Ruby?

A Use the exit keyword

B Use the stop keyword

C Use the continue keyword

D Use the break keyword

The break keyword immediately exits the loop.

Explain how a while loop works in Ruby and give a simple example.

Think about counting numbers using a variable.

What are the risks of using a while loop and how can you avoid them?

Consider what happens if the condition never changes.