2.7 KiB
2.7 KiB
Generics
Functions
- πππ
// fill in the blanks to make it work
struct A; // Concrete type `A`.
struct S(A); // Concrete type `S`.
struct SGen<T>(T); // Generic type `SGen`.
fn reg_fn(_s: S) {}
fn gen_spec_t(_s: SGen<A>) {}
fn gen_spec_i32(_s: SGen<i32>) {}
fn generic<T>(_s: SGen<T>) {}
fn main() {
// Using the non-generic functions
reg_fn(__); // Concrete type.
gen_spec_t(__); // Implicitly specified type parameter `A`.
gen_spec_i32(__); // Implicitly specified type parameter `i32`.
// Explicitly specified type parameter `char` to `generic()`.
generic::<char>(__);
// Implicitly specified type parameter `char` to `generic()`.
generic(__);
println!("Success!")
}
- ππ A function call with explicitly specified type parameters looks like:
fun::<A, B, ...>()
.
// implement the generic function below
fn sum
fn main() {
assert_eq!(5, sum(2i8, 3i8));
assert_eq!(50, sum(20, 30));
assert_eq!(2.46, sum(1.23, 1.23));
println!("Success!")
}
Struct and impl
- π
// implement struct Point to make it work
fn main() {
let integer = Point { x: 5, y: 10 };
let float = Point { x: 1.0, y: 4.0 };
println!("Success!")
}
- ππ
// modify this struct to make the code work
struct Point<T> {
x: T,
y: T,
}
fn main() {
// DON'T modify here
let p = Point{x: 5, y : "hello".to_string()};
println!("Success!")
}
- ππ
// add generic for Val to make the code work, DON'T modify the code in `main`
struct Val {
val: f64,
}
impl Val {
fn value(&self) -> &f64 {
&self.val
}
}
fn main() {
let x = Val{ val: 3.0 };
let y = Val{ val: "hello".to_string()};
println!("{}, {}", x.value(), y.value());
}
Method
- πππ
struct Point<T, U> {
x: T,
y: U,
}
impl<T, U> Point<T, U> {
// implement mixup to make it work, DON'T modify other code
fn mixup
}
fn main() {
let p1 = Point { x: 5, y: 10 };
let p2 = Point { x: "Hello", y: 'δΈ'};
let p3 = p1.mixup(p2);
assert_eq!(p3.x, 5);
assert_eq!(p3.y, 'δΈ');
println!("Success!")
}
- ππ
// fix the errors to make the code work
struct Point<T> {
x: T,
y: T,
}
impl Point<f32> {
fn distance_from_origin(&self) -> f32 {
(self.x.powi(2) + self.y.powi(2)).sqrt()
}
}
fn main() {
let p = Point{x: 5, y: 10};
println!("{}",p.distance_from_origin())
}
You can find the solutions here(under the solutions path), but only use it when you need it