Intermediate Rust Developer Interview Questions and Answer

Question 1

What is the difference between a struct and an enum in Rust

Answer 1

A struct is a data structure that groups together related data of different types into a single unit.

An enum is a data type used to represent a set of named values. Each named value in the enum is called a variant.

Question 2

How do you handle errors in Rust?

Answer 2

Result type: Rust provides a built-in Result type that enables functions to either return a value or an error. In case of an error, the function will provide information about the error.

Option type: The Option type is similar to the Result type but is used for cases where a value may or may not be present.

Panic! macro: If the program faces a fatal error, then the panic! macro mechanism helps in stopping the execution of the program and providing the relevant error message.

Rust also has several error-handling libraries, such as the standard library’s Error trait and the popular crates like thiserror, anyhow, and failure, which provide more advanced features for error handling, such as custom error types, backtraces, and error chaining.

Question 3

What is the role of the standard library in Rust?

Answer 3

The standard library in Rust contains a collection of modules offering the core functionalities of the language.

The standard library is packaged with every installation of Rust, and it provides a wide array of features such as I/O operations, data types, networking capabilities, concurrency protocols, etc.

Question 4

Explain asynchronous programming in Rust?

Answer 4

Asynchronous programming in Rust involves writing code that can execute non-blocking operations without blocking the main thread.

Question 5

Explain the concurrency model

Answer 5

The concurrency model in Rust is primarily based on the ownership and borrowing concepts ensuring memory safety and preventing usual concurrency errors like deadlocks and data races.

Question 6

How do you perform I/O in Rust?

Answer 6

The std::io module belonging to the standard library in Rust is used to perform the input/output I/O operations.

Question 7

What is the testing framework used for?

Answer 7

The testing framework in Rust provides an efficient alternative to manual testing. It comes with an in-built framework, known as rustc_test, that offers a collection of tools for testing the Rust code.

Question 8

What is the documentation system in Rust?

Answer 8

In Rust, documentation is an important part of writing code. Rust has a built-in documentation system called Rustdoc that allows developers to document their code with comments and generate HTML documentation that can be viewed in a web browser.

Rustdoc uses a syntax for documenting code called “Rustdoc comments.”

Question 9

How is multithreading handled in Rust?

Answer 9

Rust provides built-in support for multi-threading via the standard library. Rust provides threads in the form of lightweight units of execution with the capability of running concurrently within a program.

Question 10

What is a mutex in Rust?

Answer 10

Mutex is a mutual exclusion primitive that is incredibly helpful in the protection of shared data. It enables safe access to shared data across several execution threads by blocking threads waiting for the lock to become available.

Question 11

What is atomic in Rust?

Answer 11

In Rust, “atomic” refers to types that provide atomic operations, which means that these operations are guaranteed to be indivisible and thus not susceptible to race conditions or data corruption when accessed concurrently by multiple threads.

Question 12

What is a mutable reference?

Answer 12

A mutable reference is a reference to the variable that allows it to be modified. It is represented by “&mut” syntax.

Question 13

How do you work with Rust’s standard collections(Vec, HashMap, etc)?

Answer 13

Rust’s standard collections, such as Vec, HashMap, and HashSet, are commonly used in Rust programs for managing and manipulating data collections.

Vec: A Vec (“vector”) is Rust’s built-in dynamic array.

HashMap: A HashMap is Rust’s built-in hash table implementation. It allows you to store key-value pairs, where each key is unique.

HashSet: A HashSet is similar to a HashMap but only stores unique keys without any associated values.

Question 14

What is the trait system in Rust?

Answer 14

The trait system covers a collection of methods defined for a specific type. The trait system enables generic programming and code reusability.

Question 15

What is the syntax for pattern matching?

Question 16

What is the memory model in Rust?

Answer 16

The memory model in Rust is designed to provide safety and performance by enforcing a set of rules that govern how Rust code interacts with memory.

Question 17

How do you work with standard string types in Rust?

Answer 17

Rust has two main string types: String and str. The string is a growable, heap-allocated string type, while str is a string slice that is a view into a contiguous sequence of UTF-8 bytes

Question 18

How does Rust support Macros?

Answer 18

There are two macros supported by Rust: Procedural Macros and Declarative Macros.

Procedural Macros generate code at compile time through the syntax tree.

The declarative macros enable you to match patterns within the Rust code and generate a new code using those patterns.

Question 19

Explain closure in Rust.

Answer 19

In Rust, a closure is a similar function to a construct used to capture variables from the enclosing scope, and it can be passed as a value.

Question 19

What is the ownership model for closures?

Answer 19

Rust provides a unique ownership model for closures that enables the variables to be captured from the enclosing environment. When a variable is captured by closure, it takes ownership of the variable enabling it to move or modify the variable.

Rust’s different types of closures are Fn, FnMut, and FnOnce.

Question 20

How does Rust support networking?

Answer 20

IPv4 and IPv6: Rust supports IPv4 and IPv6 addresses and sockets.

HTTP: Rust has several crates for working with HTTP, including “hyper” and “request” These crates provide high-level abstractions for building HTTP clients and servers.

Question 21

How can you use Rust for web development?

Answer 21

Asynchronous programming: Rust has in-built support for asynchronous programming that enables developers to generate efficient and non-blocking code for managing multiple concurrent requests.

Web frameworks: There are many web frameworks available with Rust, including Rocket, Actix, and Warp, that offer a robust foundation for web development.

Safety: Rust has a strong safety mechanism for web development as it uses ownership and borrowing mechanisms to ensure safe memory management

Cross-platform compatibility: Rust offers cross-platform compatibility as it can be compiled across various platforms, thus making it an ideal option for web applications.

Question 21

How does Rust support database programming?

Answer 21

Diesel: Diesel is a popular Rust ORM (Object-Relational Mapping) library that provides a type-safe and composable query builder. It supports a wide range of databases, including PostgreSQL, MySQL, and SQLite

Postgres: Postgres is a Rust library for working with PostgreSQL databases. It provides a safe and ergonomic API that makes it easy to interact with Postgres.

SQLx is a Rust library that provides a unified API for working with multiple databases, including PostgreSQL, MySQL, and SQLite.

Question 21

How does Rust manage unsafe code?

Answer 21

Raw pointers: Rust provides raw pointers, similar to C, allowing developers to perform low-level operations like pointer arithmetic and casting.

Unsafe functions and methods: Rust provides several functions and methods that are marked as unsafe, meaning that they require the developer to manually ensure that they are used correctly.

Unsafe blocks: Rust allows developers to mark a code block as unsafe, allowing them to perform low-level operations that would not be allowed otherwise.

Question 22

How does Rust support generics?

Answer 22

Rust supports generics via the usage of type parameters. Type parameters enable developers to define a function or generic type without needing to write separate code for each type.

Question 23

Explain crates in Rust?

Answer 23

A crate is a compilation unit packaged within the language. It can be considered as a module or a library containing code that can be reused and shared across various Rust projects.

A crate can have multiple modules containing functions, enums, structs, and other attributes.

Question 23

What is the difference between Copy and Clone traits in Rust?

Answer 23

The Copy trait is used for types that are inexpensive to copy, like numbers, pointers, and booleans.

The Clone trait is used for types that are expensive to copy or have ownership semantics, such as strings, vectors, and other types that allocate memory on the heap.

Question 24

Explain the difference between an array and a vector

Answer 24

An array is a collection of fixed sizes of elements belonging to the same type and allocated on the stack. The size of the array must be known at compile-time and cannot be changed at runtime.

A vector, on the other hand, is a dynamic-size collection of elements of the same type, allocated on the heap. Vectors can grow or shrink in size as needed during runtime.

Question 25

Explain the difference between the module and the crate.

Answer 25

In Rust, a module is a way to organize code within a file or across multiple files, while a crate is a compilation unit in Rust that produces a binary or library.

Question 26

What is the purpose of a static lifetime?

Answer 26

In Rust, static lifetime represents the data with a global lifetime, i.e., the entire duration of the program execution. Its purpose is to ensure the data remains valid for the complete program execution, and a static lifetime specifier defines it.

Question 27

What is the difference between a mutable and an immutable reference in Rust?

Answer 27

In Rust, a mutable reference is a reference to a value that allows it to be modified, while an immutable reference is a reference to a value that cannot be modified.

Question 28

Explain the difference between trait object and generic type.

Answer 28

In Rust, a trait object and a generic type are two different mechanisms for achieving polymorphism.

A generic type is a type parameterized over one or more other types. When a function or struct is defined with a generic type, the caller can specify the concrete types used when calling the function or instantiating the struct.

A trait object, on the other hand, is a type-erased reference to an object that implements a particular trait.

Question 29

What is the difference between an iterator and a generator?

Answer 29

In Rust, an iterator is a trait that defines a sequence of elements that can be iterated over using a for loop or other iteration constructs.

On the other hand, a generator is a type of iterator that produces values lazily and on-demand instead of eagerly generating all values upfront. Generators are defined using the yield keyword and can be used to represent infinite or very large sequences.

Question 30

What is the difference between a mutable and an immutable variable in Rust?

Answer 30

A mutable variable is one whose value can be edited after the assignment, whereas an immutable variable is one whose value can’t be edited after the assignment.

Question 31

Explain smart pointer in Rust.

Answer 31

The smart pointer is a data type that provides added functionality compared to a regular pointer.

Question 32

How are slices used in Rust?

Answer 32

Slices are often used to pass a portion of a collection to a function rather than the entire collection. Slices are lightweight and efficient because they only contain a pointer at the beginning of the sequence and a length.

Question 32

What is a slice in Rust

Answer 32

A slice is a pointer or a reference to the sequence of elements in the memory block. Slices are used to access data volumes stored in contiguous sequences in memory.