Ultimate Rust Crash: Course Repack

fn calculate_length(s: &String) -> usize // & means borrow s.len() // s goes out of scope, but nothing dropped (no ownership) fn main() { let s = String::from("hello"); let len = calculate_length(&s); println!("'{}' has length {}", s, len); // s still usable } fn change(s: &mut String) s.push_str(" world");

let x = 5; let y = x; // copy, both valid let s1 = String::from("hello"); let s2 = s1.clone(); // expensive, explicit 9. Borrowing & References (Without Taking Ownership) Instead of moving, you can borrow a reference.

let mut s = String::from("hello"); change(&mut s); ultimate rust crash course

fn add(a: i32, b: i32) -> i32 a + b // no semicolon -> this is returned

By the end of this article, you will read and write basic Rust, understand ownership, and be ready to tackle real projects. Most bugs come from memory errors (use-after-free, dangling pointers, data races) or concurrency issues. Languages like C/C++ give you speed but no safety. Languages like Java/Go give you safety but with a garbage collector (GC) that adds runtime overhead. fn calculate_length(s: &String) -> usize // & means

let some_number = Some(5); let absent_number: Option<i32> = None; // You cannot add Option<i32> to i32 directly. let x: i32 = 5; let y: Option<i32> = Some(10); // let sum = x + y; // ERROR: mismatched types

fn main() let x = 5; // immutable // x = 6; // ERROR: cannot assign twice to immutable variable let mut y = 10; // mutable y = 11; // OK Most bugs come from memory errors (use-after-free, dangling

For simple types (integers, booleans, etc.) that implement the Copy trait, assignment copies instead of moves.