Rust Brain Teasers/

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Puzzle 11: Explanation

Puzzle 11: Explanation

Let’s find out how stacks and heaps work in Rust.

We'll cover the following...

Test it out

Hit “Run” to see the code’s output. The answer depends on how we run the program.

Debug mode

Pressing “Run” will cause the program to crash and display an error message:

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fn main() {
    let c = Box::new([0u32; 10_000_000]);
    println!("{}", c.len());
}

Release mode

Pressing “Run” in release mode will display the following output:

10000000

[package]
name = "boxes"
version = "0.1.0"
authors = ["Herbert Wolverson <herberticus@gmail.com>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
Running in release mode

Explanation

10,000,00010,000,000 3232-bit integers require 4040MB of memory to store. That’s ...