public/subjects/circle/README.md

## circle

### Instructions

Create the structures `Circle` and `Point` (which will be made of two coordinates) and the methods necessary for the code in [usage](#usage) to compile and run giving the expected output.

#### Methods:

- Point:
  distance() -> returns the distance between two coordinates.
- Circle:
  - diameter() -> returns the diameter of the circle.
  - area() -> returns the area of the circle.
  - intersect() -> which returns true, if 2 circles intersect.

#### Associated Functions

- Circle:
  - new() -> receives three 64 bits floating point numbers in the following order: x, y and radius (x and y are the coordinates of the center of the new circle). The function returns a new circle

### Notions

- [Using Structs](https://doc.rust-lang.org/book/ch05-00-structs.html)
- [f64 constants](https://doc.rust-lang.org/std/f64/consts/index.html)

### Expected Functions and Structures

This snippets are incomplete and it is part of the exercise to discover how to complete them. In the [usage](#usage) you will find all the information that you need.

```rust
struct Circle {
	center //..
	radius //..
}

struct Point {
// ...
}

// Point
fn distance(p1, p2) -> _ {

}

// Circle
fn new(x: f64, y: f64, radius: f64) -> Circle {
}

fn diameter(_) -> _ {
}

fn area() -> _ {
}

fn intersect(self, other: ) -> bool {
}
```

### Usage

Here is a program to test your function

```rust
use std::f64::consts;
use circle::{Circle, Point};

fn main() {
	let circle = Circle::new(500.0, 500.0, 150.0);
	let circle1 = Circle {
		center: Point { x: 80.0, y: 115.0 },
		radius: 30.0,
	};
	let point_a = Point { x: 1.0, y: 1.0 };
	let point_b = Point { x: 0.0, y: 0.0 };
	println!("circle = {:?} area = {}", circle, circle.area());
	println!("circle = {:?} diameter = {}", circle, circle.diameter());
	println!("circle1 = {:?} diameter = {}", circle1, circle1.diameter());
	println!(
		"circle and circle1 intersect = {}",
		circle.intersect(&circle1)
	);

	println!(
		"distance between {:?} and {:?} is {}",
		point_a,
		point_b,
		point_a.distance(&point_b)
	);

}
```

And its output

```console
$ cargo run
circle = Circle { center: Point { x: 500.0, y: 500.0 }, radius: 150.0 } area = 70685.83470577035
circle = Circle { center: Point { x: 500.0, y: 500.0 }, radius: 150.0 } diameter = 300
circle1 = Circle { center: Point { x: 80.0, y: 115.0 }, radius: 30.0 } diameter = 60
circle and circle1 intersect = false
distance between Point { x: 1.0, y: 1.0 } and Point { x: 0.0, y: 0.0 } is 1.4142135623730951
$
```