30+ Rust Interview Questions And Answers

Lifetimes are Rust's way of ensuring that references don't outlive the data they point to. They are important because they prevent dangling pointers at compile time and ensure memory safety without needing a garbage collector.

Yes, you use lifetimes to create a struct with references. The struct Book includes a reference to a string slice. The lifetime parameter '<a' ensures that the reference does not outlive the data it points to.

Traits in Rust are a way to define shared behavior across different types. They are similar to interfaces in other languages. You define a trait with methods that can be implemented by different types.

To implement the Display trait, you use the 'impl' keyword followed by 'fmt::Display' for your struct. Then, you define the 'fmt' function using a Formatter to write the desired output to display your struct as a string.

use std::fmt;

struct Person {
    name: String,
    age: u8,
}

impl fmt::Display for Person {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{} ({})", self.name, self.age)
    }
}

Rust's concurrency model is based on the concept of 'fearless concurrency'. It uses threads for concurrent execution but ensures safety through ownership and types. Channels provide a way for threads to communicate by sending messages between them.

iter borrows each element of the collection, into_iter takes ownership of the collection and returns owned values, and iter_mut mutably borrows each element, allowing for the collection to be modified in place.

panic! is a macro that stops execution when the program encounters an unrecoverable error, while unwrap is a method that either yields the value inside an Option or Result, or panics if they contain an Err or None.

Associated functions are functions associated with a type, like static methods in other languages, and are called using '::'. Methods are similar but are called on an instance of the type with '.', and have access to the instance's data.

Interior mutability is a design pattern in Rust that allows you to mutate data even when there are immutable references to that data, by using safe borrowing checks at runtime.

This code creates ten threads that print the number 5 to the console. It uses Arc (Atomically Reference Counted) to safely share and manage the number between multiple threads.

async/await in Rust is used for asynchronous programming. It allows programs to perform other work while awaiting the completion of some I/O operation, without blocking. This results in better resource utilization and performance.

Thread safety with mutable static variables can be ensured by using synchronization primitives like Mutex or RwLock, which provide controlled access to the data by using locking mechanisms.

PhantomData is a marker type used in generic programming to indicate that a generic type parameter is significant in a struct or enum, even though it's not directly used.

Macros in Rust are ways of writing code that writes other code (metaprogramming). Unlike functions, macros are expanded at compile time and can operate on the syntax of the code, making them more flexible but also more complex.

To optimize a Rust program, you would carefully manage memory allocation, use efficient data structures, leverage iterators to avoid unnecessary data collection, and employ profiling and benchmarking to find bottlenecks.