Variables

Variables can be created using the following syntax:

let <name>: <Type> = <value>;

Here we create the variable count as a signed 32 bit int and initialize it with the value 5:

use std::*;

fn main() {
let count: i32 = 5;
}

Type inferrence can be used to obtain the type from surrounding context:

use std::*;

fn main() {
let count: _ = 5;
}

The _ is a placeholder and can stand for any type.

If such type inferrence is successful, we can also omit the type fully:

use std::*;

fn main() {
let count = 5;
}

Integer constants may also have different types, which can again be inferred from both sides:

use std::*;

fn main() {
let a = 5usize;
let b: usize = 5;
let c: u8 = 5i8; // This does not work as the two types conflict!
}

Note: Goto numbers for more information about different usecases for different types