Error Handling (Result/Option)Beginner
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rustHow does robust Error Handling work with Result and Option in Rust?
Explanation & Concept
Rust has no `null` or exceptions. Instead, it uses standard algebraic enums:
• `Option<T>`: Represents either `Some(T)` or `None`. • `Result<T, E>`: Represents either `Ok(T)` or `Err(E)`. • The `?` operator: Ergonomic error propagation that unwraps `Ok` or immediately returns `Err`.
Code Example
rust
use std::fs::File;
use std::io::{self, Read};
fn read_username_from_file() -> Result<String, io::Error> {
let mut file = File::open("username.txt")?; // '?' propagates io::Error on failure
let mut username = String::new();
file.read_to_string(&mut username)?;
Ok(username)
}How It Works & Key Takeaways
The `?` operator makes error propagation clean and readable while keeping error handling explicit in the type system.
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