cargo fmt

The code requires the student to create a Party not  a Dessert as originally stated in the comment

Cargo.toml

@@ -1,2 +1,3 @@
 [workspace]
 members = [ "example/*", "exercise/*" ]
+resolver = "2"

README.md

@@ -1,6 +1,6 @@
 # Ultimate Rust 2: Intermediate Concepts
 
-This is the companion repository for the `Ultimate Rust 2: Intermediate Concepts` (the followup to the popular [Ultimate Rust Crash Course]).  _UR2IC_ will be published independently online in the second half of 2021 and is also presented live as part of some O'Reilly virtual events such as  [Rust in 3 Weeks], or taught in-person for corporate training.  You will get the most out of this training experience by doing the [exercises] in this repository and watching (or attending) the instructor-led training.
+This is the companion repository for the `Ultimate Rust 2: Intermediate Concepts` (the followup to the popular [Ultimate Rust Crash Course]). You will get the most out of this training experience by doing the [exercises] in this repository and watching (or attending) the instructor-led training.
 
 In other words, this repository is for you hands-on-learners!
 
@@ -22,7 +22,7 @@ The exercises are separate Rust projects inside the `exercises/` subdirectory.
 - Open up the `src/main.rs` file.
 - Follow the numbered exercise instructions in the code comments.
 
-If you encounter any problems with the exercises, please feel free to use the online course communication tools to contact me, or [open an discussion]. Either way. 😄
+If you encounter any problems with the exercises, please feel free to use the online course communication tools to contact me, or [open a discussion]. Either way. 😄
 
 For your convenience, here is a list of all the exercises, with links to view the code on GitHub.
 
@@ -55,7 +55,7 @@ If you like the work I do, please consider sponsoring me [on GitHub] or [on Patr
 
 [exercises]: https://github.com/CleanCut/ultimate_rust2#exercises
 [`example/`]: https://github.com/CleanCut/ultimate_rust2/blob/main/example
-[open an discussion]: https://github.com/CleanCut/ultimate_rust2/discussions/new
+[open a discussion]: https://github.com/CleanCut/ultimate_rust2/discussions/new
 [Ultimate Rust Crash Course]: https://agileperception.com/ultimate_rust_crash_course
 [Rust in 3 Weeks]: https://agileperception.com
 [Ultimate Rust 2: Intermediate Concepts]: https://github.com/CleanCut/ultimate_rust2

exercise/closures_iterators/src/main.rs

@@ -6,30 +6,31 @@ fn main() {
     // number multiplied by itself), and assign the closure to the "square" variable. Then run the
     // code and make sure it works.
 
-    // let square = ...
-    // println!("5 squared is {}", square(5));
+    let square = |x| x * x;
+    println!("5 squared is {}", square(5));
 
     // 2. Uncomment the code below.  Finish the .map() iterator adaptor call by passing it a closure
     // which takes a tuple of two integers as a parameter, and returns a tuple with the first
     // integer incremented by 1, and the second integer left alone.  For example, if given the input
     // (0, 1), it should return (1, 1). Run the code and make sure it works.
 
-    // let pairs = vec![(0, 1), (2, 3), (4, 5)];
-    // pairs
-    //     .into_iter()
-    //     .map( ... )
-    //     .for_each(|t| println!("{:?}", t));
+    let pairs = vec![(0, 1), (2, 3), (4, 5)];
+    pairs
+        .into_iter()
+        .map(|t| (t.0 + 1, t.1))
+        .for_each(|t| println!("{:?}", t));
 
     // 3. Uncomment the code below. There is a mutable vector named `numbers`. Use an iterator over
     // mutable references to multiply each of the values in `numbers` by 3.
     // Hint 1: You'll need .iter_mut() -- bonus points if you use the shorter, syntactic sugar form!
     // Hint 2: `x` will be a mutable reference, so remember to dereference it to use it
 
-    // let mut numbers = vec![1, 2, 3, 4];
-    // for x in ... {
-    //     ... // multiply the value by 3 via the mutable reference x
-    // }
-    // println!("{:?}", numbers); // should print [3, 6, 9, 12]
+    let mut numbers = vec![1, 2, 3, 4];
+    // numbers = numbers.iter_mut().map(|x| *x * 3).collect();
+    for n in &mut numbers {
+        *n = *n * 3;
+    }
+    println!("{:?}", numbers); // should print [3, 6, 9, 12]
 
     // 4. Uncomment the code below.  Take the vector of words and
     // - Convert the vector into an iterator with .into_iter()
@@ -39,9 +40,13 @@ fn main() {
     //
     // Hint: .to_uppercase() is a method on `str` which returns a String
 
-    // let words = vec!["autobot", "beach", "car", "decepticon", "energon", "frothy"];
-    // let transformed...  // do the stuff here
-    // println!("Transformed: {:?}", transformed);
+    let words = vec!["autobot", "beach", "car", "decepticon", "energon", "frothy"];
+    let transformed = words
+        .into_iter()
+        .filter(|w| !w.contains("h"))
+        .map(|w| w.to_uppercase())
+        .collect::<Vec<String>>();
+    println!("Transformed: {:?}", transformed);
 
     // Challenge:
     //

exercise/docs/src/lib.rs

@@ -4,10 +4,17 @@
 //
 // Once you've got the documentation here, run `cargo doc --no-deps --open` and take a look!
 
+//! A pumpkin is a cultivated winter squash in the genus Cucurbita.
+//! The term is most commonly applied to round, orange-colored squash varieties,
+//! but does not possess a scientific definition. It may be used in reference to
+//! many different squashes of varied appearance and belonging to multiple species in the Cucurbita genus.
+
 // 2. What about an image!? Add an image of a pumpkin to the end of the module-level documentation.
 // The markdown format is ![some alt text](https://url-to-the-image.png)
 // Here's the image to link to: https://upload.wikimedia.org/wikipedia/commons/thumb/5/5c/FrenchMarketPumpkinsB.jpg/700px-FrenchMarketPumpkinsB.jpg
 
+//! ![Pumpkin Image](https://upload.wikimedia.org/wikipedia/commons/thumb/5/5c/FrenchMarketPumpkinsB.jpg/700px-FrenchMarketPumpkinsB.jpg)
+
 // 3. Document the Pumpkin struct.
 // - The description on the index page should be "Big orange thing"
 // - Make a section header called "Recipes"
@@ -15,8 +22,16 @@
 // - Document the "roundness" field, explaining that it is a percentage
 // - Document the "orangeness" field, explaining that it is a number from 8 to 27
 
+/// Big orange thing
+///
+/// # Recipes
+///
+/// Recipes will be coming soon.
 pub struct Pumpkin {
+    /// `roundness` is a percentage that describes how round the pumpkin is.
+    /// 100% means perfectly round, while 0% means not round at all.
     pub roundness: f32,
+    /// `orangeness` is a number from 8 to 27 that describes how orange the pumpkin is.
     pub orangeness: i32,
 }
 
@@ -24,12 +39,14 @@ pub struct Pumpkin {
 // can't be used for pie. :'-(
 
 impl Pumpkin {
+    /// Smash the pumpkin. Once smashed, it cannot be used for pie.
     pub fn smash(self) {}
 }
 
 // 5. Document that BURNT_ORANGE is for the "orangeness" field in the Pumpkin struct.
 // - Link to the Pumpkin struct in your description
 
+/// The `BURNT_ORANGE` constant is a value of 13 that can be used for the `orangeness` field in the [Pumpkin] struct.
 pub const BURNT_ORANGE: i32 = 13;
 
 // Challenge: Find the option to pass to `cargo doc` so that documentation for this private item

exercise/errors/src/lib.rs

@@ -14,7 +14,18 @@
 // Once you have completed defining the error type correctly, you should be able to run
 // `cargo build --lib` without any build errors or warnings. Then go to main.rs and continue with #2
 
-// pub enum DolphinError...
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+#[non_exhaustive]
+pub enum DolphinError {
+    #[error("The dolphin is hungry")]
+    Hungry,
+    #[error("The dolphin is too young")]
+    TooYoung,
+    #[error("The dolphin's name is too long and annoying to say")]
+    LongName,
+}
 
 pub struct Dolphin {
     pub name: String,

exercise/errors/src/main.rs

@@ -1,30 +1,34 @@
 // START IN lib.rs!
 
 use aquarium::Dolphin;
-
+// Silence some warnings so they don't distract from the exercise.
+#[allow(clippy::vec_init_then_push)]
 // (You already did #1 in lib.rs, right?)
 //
 // 2a. Uncomment and finish the play_time function below
 // - Bring anyhow::Result into scope with a `use` statement
 // - Have the play_time function return a `Result<Vec<String>>`. The vector of Strings will
 //   represent successful outcomes of various dolphin tricks.
+use anyhow::Result;
 
-// fn play_time(dolphin: &Dolphin) -> ... {
-//     let mut responses = vec![];
-//     // 2b. Call the .say_your_name() method on `dolphin`, use `?` to unwrap the value, and push
-//     // the value onto the `responses` vector.
-//     //
-//     // let response = ...    // this can be done with an intermediate variable...
-//     // responses.push( ... ) // ...or all on one line. Either way is fine!
-//     //
-//     // 2c. Do the same thing as #2b for the .flip() method
-//     //
-//     // 2d. Do the same thing as #2b for the .shake_hands() method
-//
-//     Ok(responses)
-// }
+fn play_time(dolphin: &Dolphin) -> Result<Vec<String>> {
+    let mut responses = vec![];
+    // 2b. Call the .say_your_name() method on `dolphin`, use `?` to unwrap the value, and push
+    // the value onto the `responses` vector.
+    //
+    let response = dolphin.say_your_name()?; // this can be done with an intermediate variable...
+    responses.push(response); // ...or all on one line. Either way is fine!
+                              //
+                              // 2c. Do the same thing as #2b for the .flip() method
+    responses.push(dolphin.flip()?);
+    //
+    // 2d. Do the same thing as #2b for the .shake_hands() method
+    responses.push(dolphin.shake_hands()?);
 
-fn main() {
+    Ok(responses)
+}
+
+fn main() -> Result<()> {
     let dolphins = vec![
         Dolphin {
             name: "Augustinius".into(),
@@ -55,14 +59,23 @@ fn main() {
         // returns an Err variant the first time it is called, the try operator will return it from
         // main(), which will end the program at the first error. anyhow's Result will take care of
         // formatting the error output for us.
+
         match play_time(dolphin) {
             Ok(responses) => {
-                println!("{} did a FABULOUS PERFORMANCE!", dolphin.name);
+                println!("\n{} did a FABULOUS PERFORMANCE!", dolphin.name);
                 for response in responses {
                     println!("  {}", response);
                 }
             }
             Err(e) => println!("{} can't perform today: {}", dolphin.name, e.to_string()),
         }
+
+        // let responses = play_time(dolphin)?;
+        // println!("\n{} did a FABULOUS PERFORMANCE!", dolphin.name);
+        // for response in responses {
+        //     println!("  {}", response);
+        // }
     }
+
+    Ok(())
 }

exercise/idiomatic/src/main.rs

@@ -8,16 +8,28 @@
 
 // Challenge: Clippy doesn't find *everything*. What else would you change to make this code better?
 
-const pi:f32=3.14159265358979323846;
-fn count_to_5()->i32{let mut foo =0;loop{if foo>pi as i32{if foo > 5{break;}}foo=foo+1;}return 5;}
-fn main() {
-println!("I can count to {}", count_to_5());
+use std::f32::consts::PI;
+
+fn count_to_5() -> i32 {
+    let mut count = 0;
+    loop {
+        if count > PI as i32 && count >= 5 {
+            break;
+        }
+        count += 1;
+    }
+    count
 }
+fn main() {
+    println!("I can count to {}", count_to_5());
+}
+
 #[cfg(test)]
 mod test {
-use super::*;
-#[test]
-fn test_counting() {
-assert_eq!(count_to_5() == 5, true);
-}
+    use super::*;
+
+    #[test]
+    fn test_counting() {
+        assert_eq!(count_to_5() == 5, true);
+    }
 }

exercise/logging/Cargo.toml

@@ -4,10 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-# I'm glad you came to add the `log` dependency! I got it all ready for you, just uncomment:
-#
-# log = "0.4"
-
-# And here's the env_logger dependency that you'll need in main.rs
-#
-# env_logger = "0.9"
+log = "0.4" # I'm glad you came to add the `log` dependency! I got it all ready for you, just uncomment:
+env_logger = "0.9" # And here's the env_logger dependency that you'll need in main.rs

exercise/logging/src/lib.rs

@@ -6,6 +6,8 @@
 //
 // Hint: You need to update Cargo.toml to add the `log` dependency, first.
 
+use log::{debug, error, info, trace, warn};
+
 #[derive(Debug)]
 pub struct Frog {
     energy: u8,
@@ -15,19 +17,24 @@ pub struct Frog {
 impl Frog {
     pub fn new() -> Self {
         // 2. Use debug!() to log "A new Frog has been created"
+        debug!(target: "Frog::new", "A new Frog has been created");
         Default::default()
     }
     pub fn hop(&mut self) {
         self.energy -= 1;
         // 3. Use info!() to log that a Frog hopped, and how much energy is left
+        info!(target: "Frog::hop", "A frog hopped! It has {} energy left", self.energy);
         if self.energy == 0 {
             // 4. Use warn!() to warn that the frog will go to sleep since he ran out of energy
+            warn!(target: "Frog::hop", "The frog will go to sleep since he ran out of energy");
             self.sleep();
         }
     }
     pub fn sleep(&mut self) {
-        if !self.sleeping {
+        if self.sleeping {
             // 5. Use error!() to log a (non-fatal) error stating that the Frog is already asleep
+            error!(target: "Frog::sleep", "The frog is already asleep");
+        } else {
             self.sleeping = true;
         }
     }
@@ -36,9 +43,12 @@ impl Frog {
 impl Default for Frog {
     fn default() -> Self {
         // 6. Use trace!() to log that a default value was generated, with the debug representation
-        Frog {
+        let frog = Frog {
             energy: 5,
             sleeping: false,
-        }
+        };
+
+        trace!(target: "Frog::Default", "A default Frog value was generated: {:?}", frog);
+        frog
     }
 }

exercise/logging/src/main.rs

@@ -8,6 +8,7 @@ use frogger::Frog;
 
 fn main() {
     // 8. Initialize env_logger using the init() function at the top level of the library
+    env_logger::init();
 
     // 9. Run this program with `cargo run` and take a look at the default output.
     // - Now run it again with an explicit log level, like `RUST_LOG=info cargo run`
@@ -19,6 +20,7 @@ fn main() {
     skippy.hop();
     skippy.hop();
     skippy.sleep();
+    skippy.sleep();
 
     // Challenge: Go back to lib.rs and set the `target: ` argument for each logging call to be the
     // path to the function.  For example, `Frog::new`

exercise/testing/Cargo.toml

@@ -9,15 +9,15 @@ edition = "2021"
 # Challenge Help 1: If you choose to take on the challenge, you'll need to add `criterion` as a
 # development dependency. Here is one way to do it:
 
-# [dev-dependencies]
-# criterion = { version = "0.3", features = ["html_reports"] }
+[dev-dependencies]
+criterion = { version = "0.3", features = ["html_reports"] }
 
 # Challenge Help 2: Each benchmark needs a `[[bench]]` section with a name and disabling the harness.
 # A name "somename" will correspond with a file "benches/somename.rs"
 
-# [[bench]]
-# name = "somename"
-# harness = false
+[[bench]]
+name = "somename"
+harness = false
 
 # Challenge Help 3: The Criterion documentation has a great tutorial for how to actually write your
 # benchmark.  Don't skip the part about `black_box()`!

exercise/testing/benches/somename.rs

@@ -0,0 +1,11 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use testing::sploosh;
+
+pub fn sploosh_benchmark(c: &mut Criterion) {
+    c.bench_function("sploosh", |b| {
+        b.iter(|| sploosh(black_box(8), black_box(9), black_box(10)))
+    });
+}
+
+criterion_group!(benches, sploosh_benchmark);
+criterion_main!(benches);

exercise/testing/src/lib.rs

@@ -3,6 +3,7 @@ pub fn sploosh(x: i32, y: i32, z: i32) -> i32 {
         (x, _, _) if x < 0 => 99,
         (1, 2, 3) => 4,
         (5, 6, 7) => 3,
+        (8, 9, 10) => 7,
         (x, y, z) => x + y - z,
     }
 }
@@ -13,9 +14,11 @@ pub fn splish(a: i32, b: i32) -> i32 {
 
 // 1. Use the `cfg` attribute to mark the `test` module below as a test module
 
+#[cfg(test)]
 mod test {
     // 2. Bring all the library items into scope with a `use` statement
     // Hint: It's okay to use `*` here.
+    use super::*;
 
     // 3. Write a test function that verifies the following condition using the `assert_eq!` or
     // `assert_ne!` macros
@@ -26,10 +29,24 @@ mod test {
     // `cargo test` should run your tests and pass
     // Hint: Don't forget the `#[test]` attribute for your test function!
 
+    #[test]
+    fn test_sploosh() {
+        assert_eq!(sploosh(1, 2, 3), 4);
+        assert_ne!(sploosh(5, 6, 7), 4);
+        assert_eq!(sploosh(-1, 2, 3), 99);
+    }
+
     // 4. Write a test function that verifies the following conditions using the `assert!` macro
     // - splish(100, 10) is negative
     // - splish(40, 20) is positive
     // - splish(9, 3) is 0
+
+    #[test]
+    fn test_splish() {
+        assert!(splish(100, 10) < 0);
+        assert!(splish(40, 20) > 0);
+        assert!(splish(9, 3) == 0);
+    }
 }
 
 // 5. Create a `tests/` directory and an integration test file `tests/more_tests.rs`

exercise/testing/tests/more_tests.rs

@@ -0,0 +1,6 @@
+use testing::{splish, sploosh};
+
+#[test]
+pub fn test_sploosh_splish() {
+    assert_eq!(sploosh(splish(-1, 0), splish(1, 1), splish(3, 2)), 4);
+}

exercise/threads_channels/src/main.rs

@@ -22,8 +22,8 @@ fn main() {
     // join handle in a variable called `handle`. Once you've done this you should be able to run
     // the code and see the output from the child thread's expensive sum in the middle of the main
     // thread's processing of letters.
-    //
-    //let handle = ...
+
+    let handle = thread::spawn(|| expensive_sum(my_vector));
 
     // While the child thread is running, the main thread will also do some work
     for letter in vec!["a", "b", "c", "d", "e", "f"] {
@@ -37,17 +37,16 @@ fn main() {
     // to a variable named `result`
     // - Get the i32 out of `result` and store it in a `sum` variable.
 
-    // let result =
-    // let sum =
-    // println!("The child thread's expensive sum is {}", sum);
+    let result = handle.join();
+    let sum = result.unwrap();
+    println!("The child thread's expensive sum is {}", sum);
 
     // 3. Time for some fun with channels!
     // - Uncomment the block comment below (Find and remove the `/*` and `*/`).
     // - Create variables `tx` and `rx` and assign them to the sending and receiving ends of an
     // unbounded channel. Hint: An unbounded channel can be created with `channel::unbounded()`
 
-    /*
-        // let ...
+    let (tx, rx) = channel::unbounded();
 
     // Cloning a channel makes another variable connected to that end of the channel so that you can
     // send it to another thread. We want another variable that can be used for sending...
@@ -62,7 +61,7 @@ fn main() {
 
     // Thread A
     let handle_a = thread::spawn(move || {
-            sleep_ms(0);
+        sleep_ms(500);
         tx2.send("Thread A: 1").unwrap();
         sleep_ms(200);
         tx2.send("Thread A: 2").unwrap();
@@ -88,12 +87,40 @@ fn main() {
 
     // 5. Oops, we forgot to join "Thread A" and "Thread B". That's bad hygiene!
     // - Use the thread handles to join both threads without getting any compiler warnings.
-    */
+    let _ = handle_a.join();
+    let _ = handle_b.join();
 
     // Challenge: Make two child threads and give them each a receiving end to a channel. From the
     // main thread loop through several values and print each out and then send it to the channel.
     // On the child threads print out the values you receive. Close the sending side in the main
     // thread by calling `drop(tx)` (assuming you named your sender channel variable `tx`). Join
     // the child threads.
+
+    let (tx, rx) = channel::unbounded();
+    let rx2 = rx.clone();
+
+    let thread_a_handle = thread::spawn(move || {
+        for n in rx {
+            println!("Thread A received: {}", n);
+            sleep_ms(10);
+        }
+    });
+
+    let thread_b_handle = thread::spawn(move || {
+        for n in rx2 {
+            println!("Thread B received: {}", n);
+            sleep_ms(10);
+        }
+    });
+
+    for number in vec![1, 2, 3, 4, 5] {
+        println!("NUMBER: {}", number);
+        let _ = tx.send(number);
+    }
+    drop(tx);
+
+    let _ = thread_a_handle.join();
+    let _ = thread_b_handle.join();
+
     println!("Main thread: Exiting.")
 }

exercise/traits/src/main.rs

@@ -1,15 +1,39 @@
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Cake {
     Chocolate,
     MapleBacon,
     Spice,
 }
 
+#[derive(Debug)]
 pub struct Party {
     pub at_restaurant: bool,
     pub num_people: u8,
     pub cake: Cake,
 }
 
+impl Default for Party {
+    fn default() -> Self {
+        Self {
+            at_restaurant: true,
+            num_people: 8,
+            cake: Cake::Chocolate,
+        }
+    }
+}
+
+impl PartialEq for Party {
+    fn eq(&self, other: &Self) -> bool {
+        self.cake == other.cake
+    }
+}
+
+impl From<&Party> for Cake {
+    fn from(party: &Party) -> Self {
+        party.cake
+    }
+}
+
 fn main() {
     // 1. The code below doesn't work because Cake doesn't implement Debug.
     // - Derive the Debug trait for the Cake enum above so this code will work. Then, run the code.
@@ -23,11 +47,11 @@ fn main() {
     // function instead of moved.
     // - Hint: You may need to derive another trait in order to be able to derive the Copy trait
 
-    // match cake {
-    //     Cake::Chocolate => println!("The name's Chocolate. Dark...Chocolate."),
-    //     Cake::MapleBacon => println!("Dreams do come true!"),
-    //     Cake::Spice => println!("Great, let's spice it up!"),
-    // }
+    match cake {
+        Cake::Chocolate => println!("The name's Chocolate. Dark...Chocolate."),
+        Cake::MapleBacon => println!("Dreams do come true!"),
+        Cake::Spice => println!("Great, let's spice it up!"),
+    }
 
     // 3. Uncomment the println below. It doesn't work since the Party struct doesn't implement the
     // Debug or Default traits.
@@ -44,18 +68,19 @@ fn main() {
     // Hint: If you get stuck, there is an example at
     // https://doc.rust-lang.org/std/default/trait.Default.html#how-can-i-implement-default
 
-    // println!("The default Party is\n{:#?}", Party::default());
+    println!("The default Party is\n{:#?}", Party::default());
 
-    // 4. You prefer Maple Bacon cake. Use "struct update syntax" to create a Dessert with `cake`
+    // 4. You prefer Maple Bacon cake. Use "struct update syntax" to create a Party with `cake`
     // set to `Cake::MapleBacon`, but the rest of the values are default.
     //
     // Hint: The trick to struct update syntax is specifying the value(s) you want to customize
     // first and then ending the struct with `..Default::default()` -- but no comma after that!
 
-    // let party = Party {
-    //     ...
-    // };
-    // println!("Yes! My party has my favorite {:?} cake!", party.cake);
+    let party = Party {
+        cake: Cake::MapleBacon,
+        ..Default::default()
+    };
+    println!("Yes! My party has my favorite {:?} cake!", party.cake);
 
     // 5. Parties are "equal" if they have the same cake.
     // - Derive the PartialEq trait for the Cake enum so Cakes can be compared.
@@ -63,14 +88,15 @@ fn main() {
     // then they are equal, no matter the location or number of attendees at the party.
     // - Uncomment and run the code below.
 
-    // let other_party = Party {
-    //     at_restaurant: false,
-    //     num_people: 235,
-    //     cake: Cake::MapleBacon,
-    // };
-    // if party == other_party {
-    //     println!("Your party is just like mine!");
-    // }
+    let other_party = Party {
+        at_restaurant: false,
+        num_people: 235,
+        cake: Cake::MapleBacon,
+    };
+
+    if party == other_party {
+        println!("Your party is just like mine!");
+    }
 
     // Challenge: You would like to be able to pass a Party struct into the smell_cake() function
     // which takes a type T which implements the Into<Cake> trait.
@@ -78,20 +104,22 @@ fn main() {
     // - Implement `From<Party> for Cake` so that the function call below works.
     //
 
-    // smell_cake(party);
+    smell_cake(&party);
 
     // Challenge 2: Implement `From<&Party> for Cake` so that you can smell your cake without
     // consuming it. Change the code above to pass in a &party. Then uncomment and run the code
     // below. After all, you want to smell your cake and eat it, too!
 
-    // println!("Yum! I'm eating this cake: {:?}. Oops, I dropped it on the floor.", party.cake);
-    // drop(cake);
+    println!(
+        "Yum! I'm eating this cake: {:?}. Oops, I dropped it on the floor.",
+        party.cake
+    );
 }
 
 pub fn admire_cake(cake: Cake) {
     println!("What a nice {:?} cake! 🎂", cake);
 }
 
-// pub fn smell_cake<T: Into<Cake>>(something: T) {
-//     println!("Hmm...something smells like a {:?} cake!", something.into());
-// }
+pub fn smell_cake<T: Into<Cake>>(something: T) {
+    println!("Hmm...something smells like a {:?} cake!", something.into());
+}