Day 5: Ownership Basics

Ownership is Rust's most unique feature and enables memory safety without garbage collection.

The Three Rules of Ownership

1. Each value has an owner
2. There can only be one owner at a time
3. When the owner goes out of scope, the value is dropped

Move Semantics

When you assign a String to another variable, ownership moves:

let s1 = String::from("hello");
let s2 = s1;  // s1 is now invalid!
// println!("{}", s1);  // ERROR: s1 was moved

Clone: Deep Copy

Use .clone() to create a deep copy:

let s1 = String::from("hello");
let s2 = s1.clone();  // Both s1 and s2 are valid

The Task

The provided code has an ownership error. The take_ownership function takes ownership of the String, so the second call fails.

Fix it so both calls work and the output is 18 (9 + 9).

Requirements

• Don't change the take_ownership function signature
• Make both function calls work
• Output should be 18

Hints

• You need to clone the string before the first call
• Or restructure to create two separate strings
• message.clone() creates a copy