95 lines
2.9 KiB
Rust
95 lines
2.9 KiB
Rust
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use std::fmt::Display;
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// This is a struct that can take any type into it.
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// Only limitation is every field should be same type.
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struct Point<T> {
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x_axis: T,
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y_axis: T,
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z_axis: T,
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}
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impl<T> Point<T> {
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// This creates new point based from values that is given.
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// Their type should be anything and must be same.
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fn new(x_axis: T, y_axis: T, z_axis: T) -> Self {
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Point {
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x_axis,
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y_axis,
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z_axis,
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}
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}
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}
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// This is a struct that can take any type into it.
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// Unlike "Point" its field not have to be same type but it can also be.
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struct AnotherPoint<T, U, K> {
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x_axis: T,
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y_axis: U,
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z_axis: K,
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}
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impl<T, U, K> AnotherPoint<T, U, K> {
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// This creates new point based from values that is given.
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// Their types not have to be same, they can be anything
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fn new(x_axis: T, y_axis: U, z_axis: K) -> Self {
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AnotherPoint {
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x_axis,
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y_axis,
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z_axis,
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}
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}
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}
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fn main() {
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println!("Hello, world!");
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// It's a bit strange to explain generics without traits.
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// In short trait defines a capability.
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// Generics use traits to match capable things to achieve what generics used for.
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// Instead of defining a lot of functions, structs and enums that do similar things,
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// we define generics to match similar patterns and collapse functions, structs and enums in one.
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// Values of this "Point" variables must have same type.
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let point_1 = Point::new(1, 2, 3);
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let point_2 = Point::new(1.0, 2.0, 3.0);
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// This "AnotherPoint" type is not have limitation like "Point"
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// They can be different types.
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let another_point_1 = AnotherPoint::new(1, 2.0, 'a');
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let another_point_2 = AnotherPoint::new(1, 2, 3);
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// I can call print_point function because it's able to fit our variables
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// Every field has same type in a "Point" type.
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print_point(&point_1.x_axis, &point_1.y_axis, &point_1.z_axis);
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print_point(&point_2.x_axis, &point_2.y_axis, &point_2.z_axis);
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// I can call print_point function because it's able to fit our variables
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// Every field may be different from others in "AnotherPoint" type.
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print_point(
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&another_point_1.x_axis,
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&another_point_1.y_axis,
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&another_point_1.z_axis,
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);
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print_point(
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&another_point_2.x_axis,
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&another_point_2.y_axis,
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&another_point_2.z_axis,
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);
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}
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// This function takes at most 3 different type of values.
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// These values must include Display trait.
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// We defined this rule with "where".
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// Instead of using where we can say:
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// fn print_point<T: Display, U: Display, K: Display>(x_axis: &T, y_axis: &U, z_axis: &K)
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fn print_point<T, U, K>(x_axis: &T, y_axis: &U, z_axis: &K)
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where
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T: Display,
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U: Display,
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K: Display,
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{
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println!("{}", x_axis);
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println!("{}", y_axis);
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println!("{}", z_axis);
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}
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