Basic match usage in Rust - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Rust code using match?

Look at this Rust program. What will it print when run?

Rust

fn main() {
    let number = 3;
    match number {
        1 => println!("One"),
        2 => println!("Two"),
        3 => println!("Three"),
        _ => println!("Other"),
    }
}

A Two

B Other

C One

D Three

💡 Hint

Check which pattern matches the value 3 in the match expression.

The variable 'number' is 3, so the match arm '3 => println!("Three")' runs, printing 'Three'.

❓ Predict Output

intermediate

What does this Rust match expression return?

What value does this Rust code assign to 'result'?

Rust

fn main() {
    let x = 5;
    let result = match x {
        1..=4 => "small",
        5..=10 => "medium",
        _ => "large",
    };
    println!("{}", result);
}

A medium

B small

C large

D Compilation error

💡 Hint

Look at the range patterns and see where 5 fits.

The value 5 matches the range 5..=10, so 'medium' is assigned to 'result'.

❓ Predict Output

advanced

What is the output of this nested match in Rust?

Analyze the nested match statements and find the output.

Rust

fn main() {
    let a = Some(2);
    let b = 3;
    match a {
        Some(x) => match b {
            3 => println!("x is {} and b is three", x),
            _ => println!("x is {} and b is not three", x),
        },
        None => println!("No value for a"),
    }
}

A No value for a

B x is 2 and b is three

C x is 2 and b is not three

D Compilation error

💡 Hint

Check the values inside the nested match carefully.

Variable 'a' is Some(2), so first match arm runs. Then 'b' is 3, so inner match prints 'x is 2 and b is three'.

❓ Predict Output

advanced

What error does this Rust code produce?

What error will this Rust code cause when compiled?

Rust

fn main() {
    let num = 7;
    match num {
        1 => println!("One"),
        2 => println!("Two"),
        _ => (),
    }
}

A Error: variable 'num' not found

B Error: mismatched types

C Error: non-exhaustive patterns in match

D No error, prints nothing

💡 Hint

Think about what happens if 'num' is 7 and no match arm covers it.

The match is not exhaustive because it only covers 1 and 2, but 'num' is 7. Rust requires all cases covered or a wildcard '_'.

🧠 Conceptual

expert

How many arms does this Rust match expression have?

Count the number of arms in this Rust match expression.

Rust

fn main() {
    let val = 10;
    match val {
        1 | 2 | 3 => println!("One, two or three"),
        4..=10 => println!("Between four and ten"),
        _ => println!("Something else"),
    }
}

A 3

B 2

C 4

D 5

💡 Hint

Count each separate match arm, not the number of values in patterns.

There are three arms: one for 1|2|3, one for 4..=10, and one wildcard '_'.