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#[derive(Debug, Copy, Clone, PartialEq)]
pub struct Point<T> {
pub a : T,
pub b : T,
pub x : Option<T>,
pub y : Option<T>
}
impl<T> Point<T> {
pub fn infinity(a: T, b: T) -> Self {
Self { x: None, y: None, a: a, b: b }
}
fn is_identity(&self) -> bool {
self.x.is_none() || self.y.is_none()
}
}
trait PointOps<T> {
fn is_valid(&self) -> bool;
fn slope(&self, other: &Self) -> T;
fn tangent_slope(&self) -> T;
}
impl PointOps<f64> for Point<f64> {
fn is_valid(&self) -> bool {
self.y.and_then(|v| Some(v.powf(2.0))) ==
self.x.and_then(|v| Some(v.powf(3.0) + self.a * v + self.b))
}
fn slope(&self, other: &Self) -> f64 {
(other.y.unwrap() - self.y.unwrap()) / (other.x.unwrap() - self.x.unwrap())
}
fn tangent_slope(&self) -> f64 {
(3.0 * self.x.unwrap() * self.x.unwrap() + self.a) / (2.0 * self.y.unwrap())
}
}
fn main() {
for (x, y) in vec![(2.0, 4.0), (-1.0, -1.0), (18.0, 77.0), (5.0, 7.0)] {
let pt = Point::<f64> { x: Some(x), y: Some(y), a: a, b: b };
if pt.is_valid() {
println!("({}, {}) OK.", x, y)
} else {
println!("({}, {}) NOT OK.", x, y);
}
}
}
/*
error[E0599]: no method named `is_valid` found for type `ec::Point<f64>` in the current scope
--> src/main.rs:29:15
|
29 | if pt.is_valid() {
| ^^^^^^^^
|
::: src/ec.rs:7:1
|
7 | pub struct Point<T> {
| ------------------- method `is_valid` not found for this
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `is_valid`, perhaps you need to implement it:
candidate #1: `PointOps`
*/
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