Rust Interview Questions and Answers 2025

To manage memory safely and efficiently without a garbage collector.

It enforces rules about how references to data can be used, ensuring memory safety.

A custom data type that allows you to group related data together.

'String' is a growable, heap-allocated string, while '&str' is an immutable string slice.

A trait is a collection of methods that can be implemented for different types, similar to interfaces in other languages.

It is used for error handling, representing either a success (Ok) or an error (Err).

Cargo is the Rust package manager and build system, used for managing dependencies and building projects.

It makes items (functions, structs, etc.) public, allowing them to be accessed from other modules.

It defines a constant value that is evaluated at compile time.

It is used to bind a value to a variable, allowing for pattern matching and destructuring.

It is used to iterate over a range or collection, using the 'for item in collection' format.

It is used to execute a block of code as long as a condition is true, using the 'while condition' format.

It creates an infinite loop, which can be exited using 'break' or 'return'.

It is used to trigger a runtime error, causing the program to terminate.

It is a growable array type that can store multiple values of the same type.

It is a view into a contiguous sequence of elements, allowing you to work with a portion of an array or vector.

It is a type that can represent one of several different values, often used for defining custom data types.

It allows you to perform operations that bypass Rust's safety guarantees, such as dereferencing raw pointers.

A powerful feature that allows you to match values against patterns, often used with enums and the 'match' statement.

'Box' is for heap allocation, 'Rc' is for reference counting (single-threaded), and 'Arc' is for atomic reference counting (multi-threaded).

A closure is an anonymous function that can capture variables from its surrounding scope.

It allows you to write asynchronous code that can run concurrently without blocking the main thread.

A control flow operator that allows you to compare a value against a series of patterns and execute code based on which pattern matches.

It is used to define implementations of methods and traits for a type.

It is a shorthand for matching a value against a pattern and executing code if it matches, often used with enums.

It is used to extract the value from a 'Result' or 'Option', panicking if it is an error or None.

It is similar to 'unwrap()', but allows you to provide a custom error message if it panics.

It is used to automatically implement certain traits for a type, such as 'Debug', 'Clone', and 'Serialize'.

It is a framework for serializing and deserializing Rust data structures, often used for JSON and other formats.

It is an asynchronous runtime for Rust, providing tools for writing concurrent applications.

It provides abstractions for asynchronous programming, including futures and streams.

It is used to explicitly drop a value, freeing its resources and calling its destructor.

It creates a null pointer, which can be used with raw pointers.

It creates a null mutable pointer, which can be used with raw mutable pointers.

It writes a value to a raw pointer without dropping the previous value, allowing for unsafe memory manipulation.

It returns the size of a type in bytes, allowing you to determine memory usage.

It returns the alignment of a type in bytes, which is important for memory layout and performance.

It swaps the values of two mutable references, allowing for efficient value exchange.

It replaces a value with its default value and returns the original value, allowing for efficient value extraction.

It replaces a value with another value and returns the original value, allowing for efficient value replacement.

Lifetimes ensure that references are valid for as long as they are used, preventing dangling references.

'Copy' creates a bitwise copy of a value, while 'Clone' allows for custom cloning logic.

It ensures that a value cannot be moved in memory, often used with async programming.

It allows custom types to behave like references, enabling smart pointers to be dereferenced.

It is used to indicate that a type parameter is logically used, even if it does not appear in the struct.

'Send' allows ownership transfer between threads, while 'Sync' allows shared access from multiple threads.

It allows you to write code without the standard library, often used in embedded systems.

It is a syntax for writing asynchronous code that looks like synchronous code, using futures under the hood.

It allows you to write custom derive macros and procedural macros for code generation.

It stands for 'Clone on Write' and allows efficient handling of owned and borrowed data.

It provides interior mutability, allowing you to mutate data even when it is immutable.

It provides mutual exclusion, allowing safe access to data from multiple threads.

It allows multiple readers or one writer to access data concurrently.

It provides low-level atomic operations for safe concurrent programming.

It allows you to perform operations that the compiler cannot guarantee are safe.

It allows you to create a new name for an existing type, improving code readability.

It involves creating a tuple struct with a single field to provide type safety and abstraction.

It defines a way to sequentially access elements in a collection, enabling lazy evaluation.

They provide a way to convert between types, with 'Into' being the reciprocal of 'From'.

They allow fallible conversions between types, returning a 'Result' to handle errors.