Smart Pointers

Box

Owning a Heap Value

Box<T> stores a value on the heap while the box itself remains an ordinary owned value.

Program

Play the program to put a selected integer into a Box, dereference it, and compute from the boxed value.

box_heap_value.rs 
fn main() {
    let value = ;
    let boxed = Box::new(value);
    let doubled = *boxed * 2;
    println!("{doubled}");
}

fn main() {
    let value = ;
    let boxed = Box::new(value);
    let doubled = *boxed * 2;
    println!("{doubled}");
}

fn main() {
    let value = ;
    let boxed = Box::new(value);
    let doubled = *boxed * 2;
    println!("{doubled}");
}
Box<T> `Box<T>` owns one heap allocation containing a `T`.
dereference `*boxed` reads the value stored inside the box.
ownership When `boxed` goes out of scope, Rust drops the heap allocation.