36 lines
751 B
Rust
36 lines
751 B
Rust
// how can we store circles & rectangles in a container?
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// solution 1: use an enum; static dispatch
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#[derive(Clone, Copy)]
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struct Point(f64, f64);
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// #[derive(Clone, Copy)]
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enum Shape {
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Circle(Point, f64),
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Rectangle(Point, Point),
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}
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fn area(s: &Shape) -> f64 {
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match *s {
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Shape::Circle(_p, r) => std::f64::consts::PI * r * r,
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Shape::Rectangle(p1, p2) => ((p1.1 - p2.1) * (p1.0 - p2.0)).abs(),
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}
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}
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fn total_area(v: &[Shape]) -> f64 {
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let mut total = 0.0;
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for s in v {
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total += area(s);
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}
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total
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}
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fn main() {
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let v: Vec<Shape> = vec![
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Shape::Circle(Point(0.0, 0.0), 1.0),
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Shape::Rectangle(Point(1.0, 1.0), Point(2.0, 3.0)),
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];
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println!("{}", total_area(&v));
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}
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