Rust Ownership

Borrow a string without moving it.

Rust

fn show(value: &str) {
    println!("{}", value);
}
fn main() {
    let name = String::from("Ada");
    show(&name);
    println!("{}", name);
}

Output

Ada
Ada

Explanation

A String owns its heap allocation. Passing &name borrows it for the function call, so the caller can still use name afterward.

Explore the dry run

Guided walkthroughReady

1fn show(value: &str) {

2 println!("{}", value);

3}

4fn main() {

5 let name = String::from("Ada");

6 show(&name);

7 println!("{}", name);

8}

Start to inspect the source, values, and output. These prepared steps explain the published sample; grouped loop steps describe multiple iterations.

View the complete dry-run table

Prepared trace of the published program. Some rows group repeated iterations.
What happens	State after step	Output so far
Allocate an owned String.	`name = String("Ada")`	—
Borrow name and call show; ownership stays in main.	`name = String("Ada")`	—
show prints the borrowed string.	`name = String("Ada")`	Ada
main still owns name and prints it again.	`name = String("Ada")`	Ada Ada