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Rust Programming Language Interview Questions and Answers

By Umesh Singh
Last update: 13 Mar 2019, 26 Questions
Rust Programming Language Interview Questions

Most Frequently Asked Rust Programming Language Interview Questions

1. What are the advantages of using rust?

It is a choice of developers. To understand advantages, let’s compare Rust with the similar programming language. However, if you want to get into complete details about Rust programming language, we are also mentioning some of the Rust Programming Language Interview Questions and Answers for all. Go through it and feel like you learnt so many things today.

Rust Vs C++

Rust provides safety where C++ is not even capable enough to provide protection to its own abstraction and even the programmers to protect theirs. If any mistake is committed in C++, it shows arbitrary behaviour - technically, it means it has no meaning. Rust isolates you from that part and lets you concentrate you on the problem that you are trying to solve.

Rust Vs Java.

Automatic garbage collection provides rust with an edge over Java. Java is faster but even it can’t match with the speed of C in some domains.

Note it: Rust programming language can do it easily.

Rust Vs Python:

Good Design gives an edge to Rust over Python. Lambda can’t even hold any statement. In Rust, everything is defined in expressions, which means Language part composes in a much better way.

2. How is Rust’s Garbage Collection?

Rust uses a static garbage collector. It works on the principle of automatic memory management which means it automatically recycles the memory that will not be used again.

3. How do you get a command line argument in Rust?

The easiest way to use a command line argument in Rust is to put an iterator over the input arguments. Users can access the command line arguments by using functions such as
std::env::args_os or std::env::args

4. How do you explain Rust compared to other programming languages?

Compared to other programming languages, Rust is blazingly fast, guarantees thread safety and prevents segfaults. It’s safer than C languages and more user sophisticated than Go.

5. Could you describe some crucial features of Rust?

Move semantics, minimal runtime, efficient C bindings, trait-based generics, zero cost abstractions, pattern matching, type interface and zero cost abstractions.

6. Can you name few industry best companies that are using Rust platform?

Mozilla, 360dialog, Atlassian, Xero, Coursera, Academia, Edu, One signal and many. In 2017 & 2018 many of the tech giants such as Amazon, Dropbox, Google (Fuchsia Project), Microsoft (as a part of its new Azure IoT project), Reddit, Twitter (for team support) and more have adopted Rust.

7. Does Rust guarantee tail-call optimization?

No, Rust doesn’t guarantee TOC (Tail Call Optimization). Not even the standard library is required to compile the rust code. In these cases, the run time is similar to that of C programming language.

8. Does Rust include move constructors?

No, the values of all types in Rust are moved via memcpy. It moves everything that doesn’t have a copy constructor or doesn’t implement the copy trait.

9. How to write and run a Rust program?

Create a file name main.rs and the below-given code in it.
fn main() {
    println!("Hello, Rust!");
}


For macOS and Linux to run open terminal, put below command
$ rustc main.rs
$ ./main

10. What is Cargo in Rust?

It's a build system and package manager built for Rust users to manager projects in it. The Cargo system manages three things for users, building code, downloading the libraries, and rebuilding those libraries.

11. What’s Cargo.lock in Rust?

When a user runs cargo build command it automatically creates a file named as Cargo.lock to keep track of dependencies in the user application.

12. What string type should you use with Rust?

By far, quite a number of string types are available to be used with Rust, choosing one from these, CStr, str, Slice, CString, OsString, OsStr and Owned type, would be more preferable.

13. Could using Rust be a safer option compared to C and C++?

The most vital advantage of using Rust over C languages is its emphasis on producing safe code. As manage memory or pointer arithmetic is necessary in C programs, Rust doesn’t require any of it beginning to end. Rust allows programmers to write unsafe code, but defaulting to its safe code.

14. How do we read a file into a string?

We have to use read_to_string() method, which defines the on the Read trait in std::io

15. How does a user asynchronous input/output in Rust?

There are several libraries available providing Rust asynchronous input/output such as tokio, mio, mioco, rotor and coio-rs.

16. What’s the relation between Rust and its reusable codes?

Rust allows developers to arrange code in a way that fosters its reuse. By easy organization of modules available in Rust, which contain various structures, function and even other modules which users can use privately or make public according to their

17. What is “cargo new” purposed for?

The cargo new command is used to create a new project in Rust. Rust users can use below syntax create a sample project using Cargo.

$ cargo new project_name –bin

18. How does a user read file input efficiently in Rust?

The following function can be used to read file input efficiency in Rust.

  • read()
  • read_to_end()
  • bytes()
  • chars()
  • take()
19. Explain the rule of using &self, self and &mut self in the declaration method?

&self : when Read-only reference is required to the function.

self : When a value is to be consumed by the function.

&mut : When a value needs to be mutated by the function with consuming it.

20. Explain the significance of unwrap() everywhere function in Rust?

This function is used to handle errors that extract the volume inside an option. It’s also extremely useful for instant prototypes with any errors.

21. How to debug Rust programs?

We can use gdb or lldb to debug Rust programs as like C and C++ programming.

22. What are the Error Handling procedures in Rust?

Rust Error Handling is categorized into three parts:

  • Recoverable Error with Results : If an error occurs, the program doesn’t stop completely. Instead, it can easily be interpreted or responded.
  • Unrecoverable Errors with Panic : If something wrong goes with the code, Rust’s panic macro comes into action, shows the error message, clean the error and then quit.
  • Panic or Not to Panic : When you are dicey about calling panic or not, write the code that panics and the process will continue as 2nd.
23. Is it possible to write a complete operating system in Rust?

Yes, it’s possible to write a complete operating system in Rust. Even few of latest released operating system in recent days have used Rust as their primary programming language.

24. How to express platform-specific behaviour in Rust?

The following attributes can be used to express platform-specific behaviour in Rust.

  • target_os
  • target_family
  • target_endian
  • And so on
25. Is it possible to cross-compile in Rust?

Yes, it is possible to have cross-compilation in Rust but certain coding is required to do the cross compilation.

26. Explain the significance of deref coercion and its functioning.

It is handy coercion that that is used for automatically converting into the reference to the content from the reference to the pointer.

Some examples of deref coercion are:

  • ü &Box to &T
  • &String to &str
  • ü &Vec to &[T]
  • ü &Arc to &T
  • ü &Rc to &TW