Rust Notes — Module 1

Tue, 17 Mar 2026 00:00:00 +0000

Rust Notes — Module 1: The Basics & Ownership

Language	Memory Management	Cost
C	Manual (`malloc`/`free`)	Unsafe — use-after-free, double-free, null deref
Go	Garbage Collector	Safe, but runtime overhead (GC pauses)
Rust	Ownership system (compiler-enforced)	Safe + zero runtime cost

Rust’s core promise: memory safety at compile time, with no garbage collector.

let x = 5; // immutable — cannot be reassigned
// x = 6; // ❌ compile error

let mut y = 5; // mutable
y = 6; // ✅ fine

You can redeclare a variable with let in the same scope — this is called shadowing: