// 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+", ); } }