structs and enums

exercises/07_structs/structs3.rs

@@ -1,6 +1,3 @@
-// Structs contain data, but can also have logic. In this exercise, we have
-// defined the `Package` struct, and we want to test some logic attached to it.
-
 #[derive(Debug)]
 struct Package {
     sender_country: String,
@@ -11,8 +8,6 @@ struct Package {
 impl Package {
     fn new(sender_country: String, recipient_country: String, weight_in_grams: u32) -> Self {
         if weight_in_grams < 10 {
-            // This isn't how you should handle errors in Rust, but we will
-            // learn about error handling later.
             panic!("Can't ship a package with weight below 10 grams");
         }
 
@@ -23,15 +18,12 @@ impl Package {
         }
     }
 
-    // TODO: Add the correct return type to the function signature.
-    fn is_international(&self) {
-        // TODO: Read the tests that use this method to find out when a package
-        // is considered international.
+    fn is_international(&self) -> bool {
+        self.sender_country != self.recipient_country
     }
 
-    // TODO: Add the correct return type to the function signature.
-    fn get_fees(&self, cents_per_gram: u32) {
-        // TODO: Calculate the package's fees.
+    fn get_fees(&self, cents_per_gram: u32) -> u32 {
+        cents_per_gram * self.weight_in_grams
     }
 }
 
@@ -68,7 +60,6 @@ mod tests {
         let recipient_country = sender_country.clone();
 
         let package = Package::new(sender_country, recipient_country, 1200);
-
         assert!(!package.is_international());
     }
 

exercises/08_enums/enums1.rs

@@ -1,6 +1,10 @@
 #[derive(Debug)]
 enum Message {
-    // TODO: Define a few types of messages as used below.
+    Resize,
+    Move,
+    Echo,
+    ChangeColor,
+    Quit,
 }
 
 fn main() {

exercises/08_enums/enums2.rs

@@ -6,7 +6,11 @@ struct Point {
 
 #[derive(Debug)]
 enum Message {
-    // TODO: Define the different variants used below.
+    Resize { width: u64, height: u64 },
+    Move(Point),
+    Echo(String),
+    ChangeColor(u8, u8, u8),
+    Quit,
 }
 
 impl Message {

exercises/08_enums/enums3.rs

@@ -44,8 +44,13 @@ impl State {
     }
 
     fn process(&mut self, message: Message) {
-        // TODO: Create a match expression to process the different message
-        // variants using the methods defined above.
+        match message {
+            Message::Resize { width, height } => self.resize(width, height),
+            Message::Move(point) => self.move_position(point),
+            Message::Echo(string) => self.echo(string),
+            Message::Quit => self.quit(),
+            Message::ChangeColor(r, g, b) => self.change_color(r, g, b),
+        }
     }
 }
 

exercises/09_strings/strings1.rs

@@ -1,6 +1,6 @@
 // TODO: Fix the compiler error without changing the function signature.
 fn current_favorite_color() -> String {
-    "blue"
+    "blue".to_string()
 }
 
 fn main() {

exercises/09_strings/strings2.rs

@@ -6,7 +6,7 @@ fn is_a_color_word(attempt: &str) -> bool {
 fn main() {
     let word = String::from("green"); // Don't change this line.
 
-    if is_a_color_word(word) {
+    if is_a_color_word(&word) {
         println!("That is a color word I know!");
     } else {
         println!("That is not a color word I know.");