% Choosing your Guarantees

<small>There is a new edition of the book and this is an old link.</small>

> Smart pointers are data structures that act like a pointer, but they also have additional metadata and capabilities.
> The different smart pointers defined in Rust’s standard library provide extra functionality beyond what references provide.

```rust
let b = Box::new(5);
println!("b = {}", b);
```

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Here are the relevant sections in the new and old books:

* **[In the current edition: Ch 15.00 — Smart Pointers][2]**
* <small>[In the first edition: Ch 4.8 — Choosing your Guarantees][1]</small>


[1]: https://doc.rust-lang.org/1.30.0/book/first-edition/choosing-your-guarantees.html
[2]: ch15-00-smart-pointers.html