"Let x = ~ 10;" deprecated in Rust?

Question

"Let x = ~ 10;" deprecated in Rust?

I read this tutorial and tried the following Rust code:

fn main() {
    let x = ~10;
    println!("{:d}", *x);
}

But the compiler complains:

rustc 1.16.0 (30cf806ef 2017-03-10)
error: expected expression, found `~`
 --> <anon>:2:13
  |
2 |     let x = ~10;
  |             ^

error: unknown format trait `d`
 --> <anon>:3:22
  |
3 |     println!("{:d}", *x);
  |                      ^^

Is it let x = ~10;

already deprecated?

+3

rust

Nan Xiao 06 Apr 17 at 1:47

source to share

1 answer

Shepmaster · Accepted Answer · 2017-04-06T01:54:43+0000

It is very outdated. Rust 1.0 was released on 2015-05-15. This syntax was removed a few months earlier. This means that your tutorial has not been updated for a long time; In fact, this file was last updated on 2014-01-28! Not a good sign.

Not an outdated version of your code:

fn main() {
    let x = Box::new(10);
    println!("{}", x);
}

The sigil has ~

been replaced with specific data structures. In this case Box

.
The format specifier :d

no longer exists. Just use Display

formatter {}

.
There is no need to dereference the number in the box.

Use the official sources instead of some "outdated" link:

"Let x = ~ 10;" deprecated in Rust?

More articles: