public/subjects/rgb_match/README.md

## rgb_match

### Instructions

Implement the struct `Color` with the associated function `swap`. This function returns a `Color` with the matching values swapped.

### Expected functions

```rust
pub struct Color {
    pub r: u8,
    pub g: u8,
    pub b: u8,
    pub a: u8,
}

impl Color {
    pub fn swap(mut self, first: u8, second: u8) -> Color {

    }
}
```

### Usage

Here is a program to test your function.

```rust
use rgb_match::*;

fn main() {
    let c = Color {
        r: 255,
        g: 200,
        b: 10,
        a: 30,
    };

    println!("{:?}", c.swap(c.r, c.b));
    println!("{:?}", c.swap(c.r, c.g));
    println!("{:?}", c.swap(c.r, c.a));
    println!();
    println!("{:?}", c.swap(c.g, c.r));
    println!("{:?}", c.swap(c.g, c.b));
    println!("{:?}", c.swap(c.g, c.a));
    println!();
    println!("{:?}", c.swap(c.b, c.r));
    println!("{:?}", c.swap(c.b, c.g));
    println!("{:?}", c.swap(c.b, c.a));
    println!();
    println!("{:?}", c.swap(c.a, c.r));
    println!("{:?}", c.swap(c.a, c.b));
    println!("{:?}", c.swap(c.a, c.g));
}
```

And its output:

```console
$ cargo run
Color { r: 10, g: 200, b: 255, a: 30 }
Color { r: 200, g: 255, b: 10, a: 30 }
Color { r: 30, g: 200, b: 10, a: 255 }

Color { r: 200, g: 255, b: 10, a: 30 }
Color { r: 255, g: 10, b: 200, a: 30 }
Color { r: 255, g: 30, b: 10, a: 200 }

Color { r: 10, g: 200, b: 255, a: 30 }
Color { r: 255, g: 10, b: 200, a: 30 }
Color { r: 255, g: 200, b: 30, a: 10 }

Color { r: 30, g: 200, b: 10, a: 255 }
Color { r: 255, g: 200, b: 30, a: 10 }
Color { r: 255, g: 30, b: 10, a: 200 }

$
```

### Notions

- [patterns](https://doc.rust-lang.org/book/ch18-00-patterns.html)