Keyword let

The let keyword.

The let keyword is used to declare a variable.

Example:

let x = 3; // We create a variable named `x` with the value `3`.

By default, all variables are not mutable. If you want a mutable variable, you'll have to use the mut keyword.

Example:

let mut x = 3; // We create a mutable variable named `x` with the value `3`.

x += 4; // `x` is now equal to `7`.

For more information about the let keyword, take a look at the Rust Book.