From Novice to Rust Developer: Interview Preparation Plan

Rust: a language that makes you think differently

You've decided to conquer Rust. Excellent. This is not just another language — it's a challenge. Rust breaks the patterns we're used to seeing in Python, JavaScript, or even C++. It forces you to think about memory, safety, and concurrency at a new level.

A Rust interview is not an exam on syntax. It's a test of how you think. Interviewers want to see that you understand the philosophy of the language: ownership, borrowing, lifetimes. In this article, we'll break down real topics and questions you'll be asked, and show code examples that will help you pass the interview.

Ready? Let's go.

1. Ownership — the foundation you can't do without

The first and most important block. If you don't understand ownership — you don't understand Rust. In an interview, you will definitely be asked to explain how ownership transfer works and write code that demonstrates it.

Key ownership rules:

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• Every value in Rust has exactly one owner.
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• When the owner goes out of scope, the value is dropped.
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• Ownership can be transferred (move) or temporarily lent (borrow).
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Example: what does this code output?

fn main() {\n    let s1 = String::from("hello");\n    let s2 = s1;\n    println!("{}", s1); // Error!\n}

Correct answer: compilation error. s1 has been moved to s2, and s1 is no longer valid. The interviewer wants to hear that you understand move semantics and why Rust is so strict about this.

2. Borrowing & References

After ownership — borrowing. How to take a reference without taking ownership? And most importantly — how not to break the compiler's rules.

Borrowing rules:

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• You can have any number of immutable references (&T).
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• You can have only one mutable reference (&mut T).
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• You cannot have both &T and &mut T to the same value simultaneously.
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Example: find the error

fn main() {\n    let mut s = String::from("hello");\n    let r1 = &s;\n    let r2 = &mut s;\n    println!("{} {}", r1, r2);\n}

Error: we created an immutable reference r1, then a mutable reference r2. The compiler won't allow it. Explanation: this is protection against data races at compile time.

3. Lifetimes — the topic that scares everyone

Lifetimes are not magic. They are annotations that help the compiler understand how long references remain valid. In an interview, you'll be asked to explain why they are needed and write a function with explicit lifetime parameters.

Typical question:

Write a function that returns the longest of two strings. How would you specify lifetimes?

fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {\n    if x.len() > y.len() { x } else { y }\n}

Here 'a is a common lifetime that guarantees the returned reference will be valid as long as both input references are valid. The interviewer will appreciate it if you mention lifetime elision — when Rust infers lifetimes for simple cases.

4. Enums and Pattern Matching — the power of Rust

Rust has no null. Instead — Option<T> and Result<T, E>. In an interview, you'll be asked to write error handling using match.

Example: safe division

fn safe_divide(a: f64, b: f64) -> Option<f64> {\n    if b == 0.0 { None } else { Some(a / b) }\n}\n\nfn main() {\n    match safe_divide(10.0, 0.0) {\n        Some(result) => println!("Result: {}", result),\n        None => println!("Cannot divide by zero"),\n    }\n}

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