Variables, Constants, and Data Types

In Rust, variables are declared using the let keyword. All variables are immutable by default, which means once a value is bound to a variable, it cannot be changed. If you want to make a variable mutable, the mut keyword is used. So, if you wanted to declare a mutable variable x and assign it the value 5, you would write let mut x = 5;. Variables can also be patterned. By default in Rust, variables are block-scoped. Rust also supports several types of variable attributes.