Why modules are used in Rust - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a module named math.

Rust

mod [1] {}

Drag options to blanks, or click blank then click option'

Afn

Bmain

Cmath

Duse

Attempts:

3 left

💡 Hint

Common Mistakes

Using fn instead of a module name.

Writing use instead of mod.

The keyword mod declares a module, and math is the module name here.

2fill in blank

medium

Complete the code to use a function add from the math module.

Rust

fn main() {
    let sum = math::[1](2, 3);
    println!("Sum: {}", sum);
}

Drag options to blanks, or click blank then click option'

Aadd

Bsubtract

Cmod

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using the module name as a function.

Calling a function that does not exist.

To call a function inside a module, use module_name::function_name. Here, add is the function.

3fill in blank

hard

Fix the error by completing the code to declare a public function add inside the math module.

Rust

mod math {
    pub fn [1](a: i32, b: i32) -> i32 {
        a + b
    }
}

Drag options to blanks, or click blank then click option'

Aadd

Bsum

Cmain

Dmod

Attempts:

3 left

💡 Hint

Common Mistakes

Not using pub to make the function accessible.

Using a different function name than called.

The function name must be add to match the usage. pub makes it accessible outside the module.

4fill in blank

hard

Fill both blanks to import the add function from the math module and use it.

Rust

use crate::math::[1];

fn main() {
    let result = [2](5, 7);
    println!("Result: {}", result);
}

Drag options to blanks, or click blank then click option'

Aadd

Bsubtract

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for import and call.

Not importing the function before use.

We import add with use and then call it directly by name.

5fill in blank

hard

Fill all three blanks to create a module utils with a public function greet and call it in main.

Rust

mod [1] {
    pub fn [2]() {
        println!("Hello from utils!");
    }
}

fn main() {
    [3]();
}

Drag options to blanks, or click blank then click option'

Autils

Bgreet

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Not making the function public.

Calling the function without the correct name.

The module is named utils, the function is greet, and we call greet() in main.