Output using println macro in Rust - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print "Hello, world!" using println! macro.

Rust

fn main() {
    [1]!("Hello, world!");
}

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

Aprintln

Bprint

Cformat

Deprintln

Attempts:

3 left

💡 Hint

Common Mistakes

Using print! instead of println! which does not add a new line.

Using format! which returns a string but does not print.

The println! macro prints text followed by a new line.

2fill in blank

medium

Complete the code to print the value of variable x using println! macro.

Rust

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

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

A"x"

B"%d"

C"{x}"

D"{}"

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around variable name inside the string.

Using C-style format specifiers like %d which are not valid in Rust.

The placeholder {} is used to print variable values in println!.

3fill in blank

hard

Fix the error in the code to correctly print the sum of a and b.

Rust

fn main() {
    let a = 3;
    let b = 4;
    println!("Sum is: [1]", a + b);
}

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

A"{a + b}"

B"a + b"

C"{}"

D"sum"

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the expression inside quotes so it prints literally.

Using variable names inside braces without formatting.

The placeholder {} is needed to print the result of a + b.

4fill in blank

hard

Fill both blanks to print the name and age variables using println! macro.

Rust

fn main() {
    let name = "Alice";
    let age = 30;
    println!("Name: [1], Age: [2]", name, age);
}

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

A"{}"

B"{name}"

D"{age}"

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names inside the string placeholders instead of {}.

Using only one placeholder for two variables.

Use {} placeholders for each variable in the string.

5fill in blank

hard

Fill all three blanks to print the uppercase name, age, and a greeting message.

Rust

fn main() {
    let name = "Bob";
    let age = 25;
    println!("[1] is [2] years old. [3]!", name.to_uppercase(), age, "Hello");
}

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

A"{}"

D"{name}"

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names inside the string placeholders instead of {}.

Mismatching the number of placeholders and arguments.

Use {} placeholders for each value. The first placeholder is for the uppercase name, so {name} is incorrect inside the string, but the argument name.to_uppercase() is passed.