Rust Questions and Answers for Viva

Answer-1: Rc is single-threaded; Arc (Atomic Reference Counted) is thread-safe for multi-threading.

Answer-2: Rust's abstractions compile to efficient, low-level code without runtime overhead.

Answer-3: The async/await model simplifies asynchronous programming by allowing non-blocking execution.

Answer-4: A closure is an anonymous function that captures variables from its environment.

Answer-5: By default, all variables are immutable; use mut to make variables mutable.

Answer-6: Cow (Copy on Write) allows efficient mutation of borrowed or owned data.

Answer-7: unsafe allows operations bypassing Rust's safety checks, like dereferencing raw pointers.

Answer-8: Write test functions annotated with #[test] and run them using cargo test.

Answer-9: The derive attribute auto-generates implementations for traits like Debug and Clone.

Answer-10: The ownership model ensures a single owner for each piece of data, transferring or borrowing ownership as needed.

Answer-11: Vec is a growable, heap-allocated array type.

Answer-12: Rust uses Option types to ensure safe handling of nullable values.

Answer-13: The Drop trait defines cleanup logic for types when they go out of scope.

Answer-14: A tuple is a fixed-size collection of values of different types. Example: (i32, bool, String).

Answer-15: String is a heap-allocated, mutable UTF-8 string type.

Answer-16: String is owned and mutable; &str is borrowed and immutable.

Answer-17: Rust guarantees memory safety, thread safety, and type correctness at compile time.

Answer-18: Rust's ecosystem includes tools like Cargo, crates.io for libraries, and Rustfmt for formatting code.

Answer-19: The std library provides essential utilities like collections, I/O, and threading support.

Answer-20: Rust is popular for systems programming due to its performance, memory safety, and lack of garbage collection.

Answer-21: Rust is a systems programming language focused on safety, speed, and concurrency, developed by Mozilla.

Answer-22: Rust was created by Graydon Hoare and introduced in 2010.

Answer-23: Key features include memory safety without garbage collection, zero-cost abstractions, and concurrency support.

Answer-24: The Rust compiler is called rustc.

Answer-25: Cargo is Rust's package manager and build system.

Answer-26: Rust files use the .rs extension.

Answer-27: Use cargo run to compile and execute or rustc filename.rs to compile manually.

Answer-28: 1) Each value has one owner. 2) A value can only have one owner at a time. 3) When the owner goes out of scope, the value is dropped.

Answer-29: Borrowing allows references to a value without transferring ownership.

Answer-30: Immutable borrowing allows read-only access, while mutable borrowing allows modification of the value.

Answer-31: Lifetimes ensure that references are valid as long as they're needed, preventing dangling pointers.

Answer-32: Traits define shared behavior that types can implement.

Answer-33: Option represents a value that may or may not exist, preventing null pointer issues.

Answer-34: Result is used for error handling, representing success (Ok) or failure (Err).

Answer-35: Both extract values from Option or Result. unwrap panics on error, while expect allows custom error messages.

Answer-36: Pattern matching uses the match keyword to handle multiple possible values.

Answer-37: Enums define types with multiple possible variants. Example: enum Color { Red, Green, Blue }.

Answer-38: Rust ensures memory safety through ownership, borrowing, and lifetimes, preventing data races and dangling pointers.

Answer-39: A struct is a custom data type that groups related values. Example: struct Point { x: i32, y: i32 }.

Answer-40: struct defines fixed data fields; enum allows multiple variants with associated data.

Answer-41: Use the mod keyword. Example: mod my_module { pub fn my_function() {} }.

Answer-42: pub makes items public and accessible outside their module; private items are accessible only within their module.

Answer-43: The Iterator trait provides a way to process sequences of items, with methods like map and filter.

Answer-44: The ? operator propagates errors, simplifying error handling.

Answer-45: Macros are code templates for generating boilerplate code. Example: println! is a macro.

Answer-46: Rust handles concurrency using threads, channels, and the async/await model.

Answer-47: Smart pointers like Box, Rc, and RefCell provide ownership and borrowing capabilities with additional features.

Answer-48: Box allows heap allocation and ownership of data, useful for recursive types.

Answer-49: Rc (Reference Counted) allows multiple ownership of heap-allocated data.

Answer-50: RefCell enables mutable borrowing at runtime, even when the data is immutable.