Expression evaluation in Rust - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Rust expression?

Consider the following Rust code snippet. What will it print?

Rust

fn main() {
    let x = 5;
    let y = 10;
    let result = x + y * 2 - 3;
    println!("{}", result);
}

A 19

B 22

C 27

D 24

💡 Hint

Remember the order of operations: multiplication before addition and subtraction.

The expression is evaluated as 5 + (10 * 2) - 3 = 5 + 20 - 3 = 22.

❓ Predict Output

intermediate

What is the value of variable `z` after this code runs?

Look at this Rust code. What value does `z` hold at the end?

Rust

fn main() {
    let x = 4;
    let y = 3;
    let z = (x + y) * (x - y);
    println!("{}", z);
}

A 21

B 1

C 7

D 0

💡 Hint

Calculate inside parentheses first, then multiply.

First, (4 + 3) = 7 and (4 - 3) = 1. Then multiply: 7 * 1 = 7.

❓ Predict Output

advanced

What does this Rust code print?

Analyze this Rust code and determine its output.

Rust

fn main() {
    let a = 10;
    let b = 3;
    let c = a / b * b + a % b;
    println!("{}", c);
}

A 10

B 9

C 12

D 13

💡 Hint

Remember integer division and remainder operations.

Integer division 10 / 3 = 3, then 3 * 3 = 9, plus remainder 10 % 3 = 1, total 10.

❓ Predict Output

advanced

What is the output of this Rust code with boolean expressions?

Check the output of this Rust program.

Rust

fn main() {
    let x = true;
    let y = false;
    let result = x && !y || y && !x;
    println!("{}", result);
}

A CompilationError

B false

C SyntaxError

D true

💡 Hint

Evaluate NOT first, then AND, then OR.

x && !y is true && true = true; y && !x is false && false = false; true || false = true.

❓ Predict Output

expert

What is the output of this Rust code involving mixed types and casting?

Analyze this Rust code and determine what it prints.

Rust

fn main() {
    let x: i32 = 7;
    let y: f64 = 2.5;
    let z = x as f64 * y;
    println!("{}", z);
}

A 17.5

B SyntaxError

C 15

D 12.5

💡 Hint

Casting changes types before multiplication. Check the order carefully.

x as f64 = 7.0, y = 2.5, so 7.0 * 2.5 = 17.5.