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// 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+",
);
}
}
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