[Easy to understand series | rustlang language | zero-based | Getting Started | (11)]
Interestingly basics
Structs
Today we take a look at data structures: structs.
Briefly, structs, is used to encapsulate a data type related data.
Generally, struct naming hump means such as: CamelCase
There are several definitions in Rust struct way:
- Structs-like C (in the form of C language struct)
- Tuple structs (struct element in the form of group)
- Structs Unit (struct units)
In in Rust, an abstract object-oriented, and is generally implemented by a struct trait (features), i.e. to structs
Attribute data package, and packages for trait, then be correlated by impl.
Let's look at the code:
C-style struct
// Struct Declaration
struct Color {
red: u8,
green: u8,
blue: u8
}
fn main() {
// Creating an instance
let black = Color {red: 0, green: 0, blue: 0};
// Accessing its fields using dot notation
println!("Black = rgb({}, {}, {})", black.red, black.green, black.blue); //Black = rgb(0, 0, 0)
// Structs are immutable by default, use `mut` to make it mutable but doesn't support field level mutability
let mut link_color = Color {red: 0,green: 0,blue: 255};
link_color.blue = 238;
println!("Link Color = rgb({}, {}, {})", link_color.red, link_color.green, link_color.blue); //Link Color = rgb(0, 0, 238)
// Copy elements from another instance
let blue = Color {blue: 255, .. link_color};
println!("Blue = rgb({}, {}, {})", blue.red, blue.green, blue.blue); //Blue = rgb(0, 0, 255)
// Destructure the instance using a `let` binding, this will not destruct blue instance
let Color {red: r, green: g, blue: b} = blue;
println!("Blue = rgb({}, {}, {})", r, g, b); //Blue = rgb(0, 0, 255)
// Creating an instance via functions & accessing its fields
let midnightblue = get_midnightblue_color();
println!("Midnight Blue = rgb({}, {}, {})", midnightblue.red, midnightblue.green, midnightblue.blue); //Midnight Blue = rgb(25, 25, 112)
// Destructure the instance using a `let` binding
let Color {red: r, green: g, blue: b} = get_midnightblue_color();
println!("Midnight Blue = rgb({}, {}, {})", r, g, b); //Midnight Blue = rgb(25, 25, 112)
}
fn get_midnightblue_color() -> Color {
Color {red: 25, green: 25, blue: 112}
}
Tuples of the form struct
struct Color(u8, u8, u8);
struct Kilometers(i32);
fn main() {
// Creating an instance
let black = Color(0, 0, 0);
// Destructure the instance using a `let` binding, this will not destruct black instance
let Color(r, g, b) = black;
println!("Black = rgb({}, {}, {})", r, g, b); //black = rgb(0, 0, 0);
// Newtype pattern
let distance = Kilometers(20);
// Destructure the instance using a `let` binding
let Kilometers(distance_in_km) = distance;
println!("The distance: {} km", distance_in_km); //The distance: 20 km
}
Struct unit
struct Electron;
fn main() {
let x = Electron;
}
Above, I hope useful to you.
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