Mutable variables in Rust - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a mutable variable named count with initial value 5.

Rust

let [1] count = 5;

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

Avar

Bmut

Cconst

Dlet

Attempts:

3 left

💡 Hint

Common Mistakes

Using var instead of let.

Forgetting to add mut for mutability.

Using const which creates an immutable constant.

In Rust, to declare a mutable variable, you use let mut. The keyword mut makes the variable mutable.

2fill in blank

medium

Complete the code to change the value of the mutable variable score to 10.

Rust

let mut score = 5;
score [1] 10;

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

A=>

B==

C=

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of = for assignment.

Using => which is not valid here.

To assign a new value to a mutable variable in Rust, use the single equals sign =.

3fill in blank

hard

Fix the error in the code by making the variable name mutable so it can be changed.

Rust

[1] name = "Alice";
name = "Bob";

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

Alet mut

Bconst

Cmut

Dvar

Attempts:

3 left

💡 Hint

Common Mistakes

Using only mut without let.

Using const which is immutable.

Using var which is not valid in Rust.

In Rust, to declare a mutable variable, you write let mut before the variable name.

4fill in blank

hard

Fill both blanks to create a mutable variable temperature and assign it the value 25.

Rust

[1] [2] temperature = 25;

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

Alet

Bmut

Cvar

Dconst

Attempts:

3 left

💡 Hint

Common Mistakes

Using var which is not valid in Rust.

Using const which creates an immutable variable.

Swapping the order of let and mut.

The correct way to declare a mutable variable in Rust is let mut followed by the variable name.

5fill in blank

hard

Fill all three blanks to declare a mutable variable speed, assign it 30, and then update it to 50.

Rust

[1] [2] speed = 30;
speed [3] 50;

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

Alet

Bmut

C=

Dconst

Attempts:

3 left

💡 Hint

Common Mistakes

Using const instead of let.

Forgetting mut to allow changing the variable.

Using == instead of = for assignment.

Declare a mutable variable with let mut, assign initial value with =, and update it with =.