quiz3 solution

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+",
+        );
+    }
+}