Loop labels in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a loop label in Rust?

A loop label is a name given to a loop so you can refer to it explicitly, especially useful to control nested loops by breaking or continuing a specific loop.

beginner

How do you define a loop label in Rust?

You define a loop label by writing an apostrophe followed by the label name before the loop keyword, like 'label_name: loop { ... }.

beginner

How do you break out of a specific labeled loop in Rust?

Use break 'label_name; to exit the loop with that label, even if it is nested inside other loops.

intermediate

What happens if you use continue 'label_name; inside nested loops?

It skips the rest of the current iteration of the labeled loop and starts the next iteration of that loop, not just the innermost loop.

beginner

Why are loop labels useful in nested loops?

They let you control which loop to break or continue, avoiding confusion and making your code clearer when dealing with multiple loops inside each other.

How do you start a loop with a label named 'outer' in Rust?

A label outer: loop { ... }

B 'outer: loop { ... }

C loop 'outer { ... }

D loop label 'outer { ... }

The correct syntax is an apostrophe followed by the label name before the loop keyword, like 'outer: loop { ... }.

What does break 'outer; do inside nested loops?

A Breaks out of the loop labeled 'outer'

B Breaks out of the innermost loop only

C Continues the loop labeled 'outer'

D Causes a syntax error

It breaks out of the loop that has the label 'outer', regardless of nesting.

Which keyword is used with a loop label to skip to the next iteration of that loop?

A break

B skip

C continue

D next

The keyword 'continue' is used with a loop label to skip the rest of the current iteration and start the next iteration of the labeled loop.

Can you use loop labels with all kinds of loops in Rust?

A No, only with infinite loops

B Only with for loops

C Only with the 'loop' keyword loops

D Yes, with any loop including for, while, and loop

Loop labels can be used with any loop type: for, while, and loop.

What is the main benefit of using loop labels in nested loops?

A To control which loop to break or continue

B To create infinite loops

C To avoid using break statements

D To make loops run faster

Loop labels help you specify exactly which loop to break or continue, which is very helpful in nested loops.

Explain how loop labels work in Rust and why they are useful.

Think about how you control loops inside loops.

Describe the difference between using break and continue with loop labels.

Consider what happens to the loop after each keyword.