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Motivation ---------- I'm currently doing the rustlings course. I was pretty lost at quiz3 because I did not understand the problem. With this change I would have understood that it should be possible to use both `f32` or `&str` for the grade. I also googled quiz3 and found that other people got confused and used enums: https://www.reddit.com/r/learnrust/comments/wccx7s/rustlings_blocked_on_quiz3/ <details> <summary>My solution, hopefully I got it now</summary> ``` // quiz3.rs // // 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. Change the Grade in the second test to // "A+" to show that your changes allow alphabetical grades. // // Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint. // I AM NOT DONE use std::fmt::Display; pub struct ReportCard<T: Display> { pub grade: T, pub student_name: String, pub student_age: u8, } impl <T: Display> ReportCard<T> { pub fn print(&self) -> String { format!("{} ({}) - achieved a grade of {}", &self.student_name, &self.student_age, &self.grade) } } 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() { // TODO: Make sure to change the grade here after you finish the exercise. 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+" ); } } ``` </details>
63 lines
1.6 KiB
Rust
63 lines
1.6 KiB
Rust
// quiz3.rs
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//
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// This quiz tests:
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// - Generics
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// - Traits
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//
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// An imaginary magical school has a new report card generation system written
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// in Rust! Currently the system only supports creating report cards where the
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// student's grade is represented numerically (e.g. 1.0 -> 5.5). However, the
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// school also issues alphabetical grades (A+ -> F-) and needs to be able to
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// print both types of report card!
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//
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// Make the necessary code changes in the struct ReportCard and the impl block
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// to support alphabetical report cards.
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//
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// Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
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// I AM NOT DONE
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pub struct ReportCard {
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pub grade: f32,
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pub student_name: String,
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pub student_age: u8,
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}
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impl ReportCard {
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pub fn print(&self) -> String {
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format!("{} ({}) - achieved a grade of {}",
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&self.student_name, &self.student_age, &self.grade)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn generate_numeric_report_card() {
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let report_card = ReportCard {
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grade: 2.1,
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student_name: "Tom Wriggle".to_string(),
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student_age: 12,
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};
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assert_eq!(
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report_card.print(),
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"Tom Wriggle (12) - achieved a grade of 2.1"
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);
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}
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#[test]
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fn generate_alphabetic_report_card() {
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let report_card = ReportCard {
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grade: "A+",
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student_name: "Gary Plotter".to_string(),
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student_age: 11,
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};
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assert_eq!(
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report_card.print(),
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"Gary Plotter (11) - achieved a grade of A+"
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);
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}
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}
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