Declare in Rust 1.55

In Rust, a class is called a struct. To declare a struct, you can use the struct keyword followed by the name of the struct and its properties inside curly braces.

Here is an example of how to declare a simple struct in Rust:

struct Person {
    name: String,
    age: u8,
    id_number: u32,
}

In this example, we declared a struct named Person with three properties: name of type String, age of type u8, and id_number of type u32.

To create an instance of this struct, we can use the new method like so:

let person = Person {
    name: String::from("John Doe"),
    age: 30,
    id_number: 1234567890,
};

This creates a new Person with the given values for each property.

You can also define methods for your struct by using the impl keyword like so:

impl Person {
    fn is_adult(&self) -> bool {
        self.age >= 18
    }
}

In this example, we defined a method named is_adult that takes a reference to self and returns a boolean indicating whether or not the person is an adult (age 18 or older).

You can use this method on a Person instance like so:

let person = Person {
    name: String::from("John Doe"),
    age: 30,
    id_number: 1234567890,
};
println!("{}", person.is_adult());

// Output: true