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Kacper Poneta 2024-12-14 08:15:40 +09:00 committed by GitHub
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@ -116,6 +116,8 @@ bin = [
{ name = "generics1_sol", path = "../solutions/14_generics/generics1.rs" },
{ name = "generics2", path = "../exercises/14_generics/generics2.rs" },
{ name = "generics2_sol", path = "../solutions/14_generics/generics2.rs" },
{ name = "generics3", path = "../exercises/14_generics/generics3.rs" },
{ name = "generics3_sol", path = "../solutions/14_generics/generics3.rs" },
{ name = "traits1", path = "../exercises/15_traits/traits1.rs" },
{ name = "traits1_sol", path = "../solutions/15_traits/traits1.rs" },
{ name = "traits2", path = "../exercises/15_traits/traits2.rs" },

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@ -0,0 +1,54 @@
// generics3.rs
// Execute `rustlings hint generics3` or use the `hint` watch subcommand for a hint.
// This function should take an array of `Option` elements and returns array of not None elements
// TODO fix this function signature
fn into_dispose_nulls(list: Vec<Option<&str>>) -> Vec<&str> {
list.into_iter().flatten().collect()
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn store_str_on_list() {
let names_list = vec![Some("maria"), Some("jacob"), None, Some("kacper"), None];
let only_values = into_dispose_nulls(names_list);
assert_eq!(only_values.len(), 3);
}
#[test]
fn store_numbers_on_list() {
let numbers_list = vec![Some(1), Some(2), None, Some(3)];
let only_values = into_dispose_nulls(numbers_list);
assert_eq!(only_values.len(), 3);
}
#[test]
fn store_custom_type_on_list() {
#[allow(dead_code)]
struct Rectangle {
width: i32,
height: i32,
}
impl Rectangle {
fn new(width: i32, height: i32) -> Self {
Self { width, height }
}
}
let custom_list = vec![
Some(Rectangle::new(1, 2)),
None,
None,
Some(Rectangle::new(3, 4)),
];
let only_values = into_dispose_nulls(custom_list);
assert_eq!(only_values.len(), 2);
}
}

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@ -745,6 +745,17 @@ hint = """
Related section in The Book:
https://doc.rust-lang.org/book/ch10-01-syntax.html#in-method-definitions"""
[[exercises]]
name = "generics3"
dir = "14_generics"
hint = """
Vectors in Rust use generics to create dynamically-sized arrays of any type.
The `into_dispose_nulls` function takes a vector as an argument, but only accepts vectors that store the &str type.
To allow the function to accept vectors that store any type, you can leverage your knowledge about generics.
If you're unsure how to proceed, please refer to the Rust Book at:
https://doc.rust-lang.org/book/ch10-01-syntax.html#in-function-definitions.
"""
# TRAITS
[[exercises]]

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@ -0,0 +1,53 @@
// generics3.rs
// Execute `rustlings hint generics3` or use the `hint` watch subcommand for a hint.
// Here we added generic type `T` to function signature
// Now this function can be used with vector of any
fn into_dispose_nulls<T>(list: Vec<Option<T>>) -> Vec<T> {
list.into_iter().flatten().collect()
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn store_str_on_list() {
let names_list = vec![Some("maria"), Some("jacob"), None, Some("kacper"), None];
let only_values = into_dispose_nulls(names_list);
assert_eq!(only_values.len(), 3);
}
#[test]
fn store_numbers_on_list() {
let numbers_list = vec![Some(1), Some(2), None, Some(3)];
let only_values = into_dispose_nulls(numbers_list);
assert_eq!(only_values.len(), 3);
}
#[test]
fn store_custom_type_on_list() {
struct Rectangle {
width: i32,
height: i32,
}
impl Rectangle {
fn new(width: i32, height: i32) -> Self {
Self { width, height }
}
}
let custom_list = vec![
Some(Rectangle::new(1, 2)),
None,
None,
Some(Rectangle::new(3, 4)),
];
let only_values = into_dispose_nulls(custom_list);
assert_eq!(only_values.len(), 2);
}
}