Ownership and Functions

How ownership transfers when passing values to functions.

Difficulty

Beginner

Code

fn take_ownership(s: String) {
    println!("took ownership of: {}", s);
}

fn give_back(s: String) -> String {
    println!("giving back: {}", s);
    s
}

fn main() {
    let s = String::from("hello");
    take_ownership(s);
    // s is no longer valid here

    let s2 = String::from("world");
    let s3 = give_back(s2);
    println!("got back: {}", s3);
}

Explanation

Passing values to functions moves ownership. Functions can return ownership.

Key Concepts

• Read the code carefully and understand the data flow
• Try modifying the example to see how it changes behavior
• Run this code in the Rust Playground

Related Topics

Browse more examples in the ownership category to build a complete understanding of this topic.