Module visibility in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the pub keyword do in Rust modules?

The pub keyword makes a module, function, or item visible outside its current module, allowing other parts of the program to access it.

beginner

What is the default visibility of items inside a Rust module?

By default, items inside a Rust module are private and cannot be accessed from outside the module unless marked with pub.

intermediate

How do you make a nested module visible outside its parent module?

You must mark both the nested module and its parent module as pub to make the nested module accessible from outside.

intermediate

Explain the difference between pub(crate) and pub in Rust module visibility.

pub(crate) makes an item visible only within the current crate (project), while pub makes it visible everywhere, including other crates.

beginner

Can a private function inside a public module be accessed from outside the module?

No, private functions inside a public module remain inaccessible from outside. Only items marked pub are accessible externally.

What keyword makes a Rust module accessible from other modules?

A use

B mod

C pub

D extern

The pub keyword makes modules and items accessible from outside their current module.

If a module is declared as pub but a function inside it is not, can the function be accessed outside?

A No, because the function is private

B Yes, because the module is public

C Only if the function is called inside the module

D Only if the function is marked <code>pub(crate)</code>

Functions are private by default and must be marked pub to be accessible outside their module.

What does pub(crate) mean in Rust?

A Visible only inside the current crate

B Visible only inside the current module

C Visible everywhere including other crates

D Visible only to external crates

pub(crate) restricts visibility to the current crate (project).

How do you make a nested module accessible outside its parent module?

A Use <code>use</code> keyword

B Mark only the parent module as <code>pub</code>

C Mark only the nested module as <code>pub</code>

D Mark both parent and nested modules as <code>pub</code>

Both parent and nested modules must be pub to be accessible externally.

What is the default visibility of a Rust module item?

A Public

B Private

C Crate-wide

D External

By default, items are private and not accessible outside their module.

Explain how Rust controls access to modules and their contents using visibility keywords.

Think about how you protect your personal stuff in a room and decide who can enter.

Describe the steps to make a nested module and its functions accessible from outside the crate.

Visibility works like unlocking doors in a house to let guests in.