Scope of variables in Rust - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable inside the main function.

Rust

fn main() {
    let [1] = 5;
    println!("Value: {}", x);
}

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

A5

Bx

Clet

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of a variable name.

Trying to use a keyword like 'let' as the variable name.

The variable name x is declared with let inside main. This makes it accessible within the function.

2fill in blank

medium

Complete the code to print the variable declared inside the block.

Rust

fn main() {
    {
        let y = 10;
        println!("[1]: {}", y);
    }
}

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

Ay

Bz

Cx

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name not declared in the block.

Trying to print a variable declared outside the block.

The variable y is declared inside the block and can be used there. So we print y.

3fill in blank

hard

Complete the code to attempt accessing the variable outside its scope and observe the error.

Rust

fn main() {
    {
        let z = 15;
    }
    println!("Value: {}", [1]);
}

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

Az

B15

Cvalue

Dlet

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to use z outside its block (this is expected to error).

Using a literal number where a variable is expected.

The variable z is out of scope outside the block, so using it causes a compile error: 'z not found in this scope'.

4fill in blank

hard

Fill both blanks to declare and use a variable inside a nested block.

Rust

fn main() {
    let [1] = 20;
    {
        println!("[2] inside block: {}", [1]);
    }
}

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

Anum

Bvalue

Dnumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for declaration and print label.

Using a variable name not declared.

The variable num is declared outside the nested block and is accessible inside it. The print label matches for clarity.

5fill in blank

hard

Fill all three blanks to declare a variable, declare another based on it, and print both values.

Rust

fn main() {
    let [1] = 5;
    let [2] = [1] + 10;
    println!("Original: {}, Second: {}", [1], [2]);
}

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

Ax

By

Dz

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable name for both declarations.

Mixing up variable names in the print statement.

The variable x is declared first (=5). Then y is declared as x + 10 (=15). Both are in scope for printing.