Ownership Rules at a Glance

Snippet

Ownership Rules at a Glance

Ownership is Rust's unique memory management system. When you assign s1 to s2, ownership moves. s1 is no longer valid. Borrowing with & allows referencing without transferring ownership.

snippet.rs
rust
fn main() {
    let s1 = String::from("hello");
    let s2 = s1;  // s1 is moved to s2
    
    // println!("{}", s1); // This would error!
    println!("{}", s2);  // This works fine
    
    let s3 = String::from("world");
    let s4 = &s3;  // Borrowing with reference
    println!("{} and {}", s3, s4);  // Both accessible
}

Breakdown

let s2 = s1;

Ownership of s1 moves to s2; s1 is invalidated

// println!("{}", s1); // ERROR

Commented line would cause compile error

let s4 = &s3;

Creates a reference to s3 without taking ownership

println!("{} and {}", s3, s4);

Both s3 and s4 are valid because of borrowing

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Ownership Rules at a Glance

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