diff options
| -rw-r--r-- | exercises/quizzes/quiz3.rs | 18 | ||||
| -rw-r--r-- | rustlings-macros/info.toml | 12 | ||||
| -rw-r--r-- | solutions/quizzes/quiz3.rs | 70 |
3 files changed, 87 insertions, 13 deletions
diff --git a/exercises/quizzes/quiz3.rs b/exercises/quizzes/quiz3.rs index f3cb1bc..c877c5f 100644 --- a/exercises/quizzes/quiz3.rs +++ b/exercises/quizzes/quiz3.rs @@ -3,26 +3,27 @@ // - Traits // // An imaginary magical school has a new report card generation system written -// in Rust! Currently the system only supports creating report cards where the +// in Rust! Currently, the system only supports creating report cards where the // student's grade is represented numerically (e.g. 1.0 -> 5.5). However, the // school also issues alphabetical grades (A+ -> F-) and needs to be able to // print both types of report card! // -// Make the necessary code changes in the struct ReportCard and the impl block -// to support alphabetical report cards. Change the Grade in the second test to -// "A+" to show that your changes allow alphabetical grades. +// Make the necessary code changes in the struct `ReportCard` and the impl +// block to support alphabetical report cards in addition to numerical ones. +// TODO: Adjust the struct as described above. struct ReportCard { grade: f32, student_name: String, student_age: u8, } +// TODO: Adjust the impl block as described above. impl ReportCard { fn print(&self) -> String { format!( "{} ({}) - achieved a grade of {}", - &self.student_name, &self.student_age, &self.grade + &self.student_name, &self.student_age, &self.grade, ) } } @@ -44,21 +45,20 @@ mod tests { }; assert_eq!( report_card.print(), - "Tom Wriggle (12) - achieved a grade of 2.1" + "Tom Wriggle (12) - achieved a grade of 2.1", ); } #[test] fn generate_alphabetic_report_card() { - // TODO: Make sure to change the grade here after you finish the exercise. let report_card = ReportCard { - grade: 2.1, + grade: "A+", student_name: "Gary Plotter".to_string(), student_age: 11, }; assert_eq!( report_card.print(), - "Gary Plotter (11) - achieved a grade of A+" + "Gary Plotter (11) - achieved a grade of A+", ); } } diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml index 92c878f..bed2eaf 100644 --- a/rustlings-macros/info.toml +++ b/rustlings-macros/info.toml @@ -805,10 +805,16 @@ https://doc.rust-lang.org/book/ch10-02-traits.html#specifying-multiple-trait-bou name = "quiz3" dir = "quizzes" hint = """ -To find the best solution to this challenge you're going to need to think back -to your knowledge of traits, specifically 'Trait Bound Syntax' +To find the best solution to this challenge, you need to recall your knowledge +of traits, specifically "Trait Bound Syntax": +https://doc.rust-lang.org/book/ch10-02-traits.html#trait-bound-syntax -You may also need this: `use std::fmt::Display;`.""" +Here is how to specify a trait bound for an implementation block: +`impl<T: Trait1 + Trait2 + …> for Foo<T> { … }` + +You may need this: +`use std::fmt::Display;` +""" # LIFETIMES diff --git a/solutions/quizzes/quiz3.rs b/solutions/quizzes/quiz3.rs index 4e18198..e3413fd 100644 --- a/solutions/quizzes/quiz3.rs +++ b/solutions/quizzes/quiz3.rs @@ -1 +1,69 @@ -// Solutions will be available before the stable release. Thank you for testing the beta version 🥰 +// This quiz tests: +// - Generics +// - Traits +// +// An imaginary magical school has a new report card generation system written +// in Rust! Currently, the system only supports creating report cards where the +// student's grade is represented numerically (e.g. 1.0 -> 5.5). However, the +// school also issues alphabetical grades (A+ -> F-) and needs to be able to +// print both types of report card! +// +// Make the necessary code changes in the struct `ReportCard` and the impl +// block to support alphabetical report cards in addition to numerical ones. + +use std::fmt::Display; + +// Make the struct generic over `T`. +struct ReportCard<T> { + // ^^^ + grade: T, + // ^ + student_name: String, + student_age: u8, +} + +// To be able to print the grade, it has to implement the `Display` trait. +impl<T: Display> ReportCard<T> { + // ^^^^^^^ require that `T` implements `Display`. + fn print(&self) -> String { + format!( + "{} ({}) - achieved a grade of {}", + &self.student_name, &self.student_age, &self.grade, + ) + } +} + +fn main() { + // You can optionally experiment here. +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn generate_numeric_report_card() { + let report_card = ReportCard { + grade: 2.1, + student_name: "Tom Wriggle".to_string(), + student_age: 12, + }; + assert_eq!( + report_card.print(), + "Tom Wriggle (12) - achieved a grade of 2.1", + ); + } + + #[test] + fn generate_alphabetic_report_card() { + let report_card = ReportCard { + grade: "A+", + student_name: "Gary Plotter".to_string(), + student_age: 11, + }; + assert_eq!( + report_card.print(), + "Gary Plotter (11) - achieved a grade of A+", + ); + } +} |