Integer conversions in Rust

Question

fn main() {
    let a: usize = 100;
    let b: u32 = 100;
    let z: i32 = a*b;
}

How do I tell the compiler which type I want there?

what do you mean with: ***which type I want there?***.... z is a i32, that is what you want isnt?? — ΦXocę 웃 Пepeúpa ツ, Feb 27 '20 at 16:24
@ΦXocę웃Пepeúpaツ what? I don't understand your english. — Pablo Tato Ramos, Feb 27 '20 at 16:27

score 1 · Accepted Answer · answered Feb 27 '20 at 16:19

1

How do I tell the compiler which type I want there?

You cast the variable to proper type. For example if you want to do the multiplication as i32 type, you would:

let z: i32 = (a as i32) * (b as i32);

More about casting is available in Rust manual - Casting.

answered Feb 27 '20 at 16:19

KamilCuk

1

Thank you. Why does the compiler suggest `try_into()` if this is simpler? – Pablo Tato Ramos Feb 27 '20 at 16:52
Because conversions with `as` may panic (in debug mode) or cause wrong results (in release mode) if the inputs don't fit in the requested type. – Jmb Feb 28 '20 at 08:19

1 Answers1