How to Create Enums in Rust

1. Declare an enum in Rust
2. Initialize enum With Values in Rust
3. Benefits of enum in Rust

Enums are a way of representing a set of related values. In Rust, they are implemented as an integral type with variants.

The enum keyword is used to create an enum type, and the variant keyword is used to declare variants. The variant can contain any number of constants called enumerators, and variants can also have methods, which are called associated functions or associated constants.

In this article, we’ll discuss the Rust Enums concept.

Declare an enum in Rust

The enum keyword is used to create an enumeration. It can be used to define a type with several different values.

1. Create the enum definition with the enum keyword, followed by the name of the enumerated type, followed by a list of values in curly braces({}).
2. Create instances of this type with the same name as the type and then assign each instance a value from its corresponding list.
3. The case keyword is used to create branches in an enum definition.

Initialize enum With Values in Rust

We assign an enum with a value to a variable to initialize it with values. The enum name is written first, followed by the double colon operators and the enum value name.

Finally, a value is specified within parentheses.

Example Code:

#[derive(Debug)]
enum Demo {
    A(i32),
    B(i32)
}
fn main() {
    let hello = Demo::A(1);
    let byew = Demo::B(0);
    println!("Hello: {:?}", hello);
    println!("Bye: {:?}", byew);
}

Output:

Hello: A(1)
Bye: B(0)

Run Code

Benefits of enum in Rust

An enum is a data type containing a set of related values. It is like an array, but you don’t have to worry about running out of space or re-allocating memory when adding more items.

Enums are better because they are more explicit and less error-prone than using a string for every possible value. Enums also allow for compile-time checks that ensure you do not assign the wrong type to a variable or misspell one of the variants in your code.