feat: progress iterators

exercises/13_error_handling/errors1.rs

@@ -4,12 +4,12 @@
 // construct to `Option` that can be used to express error conditions. Change
 // the function signature and body to return `Result<String, String>` instead
 // of `Option<String>`.
-fn generate_nametag_text(name: String) -> Option<String> {
+fn generate_nametag_text(name: String) -> Result<String, String> {
     if name.is_empty() {
         // Empty names aren't allowed
-        None
+        Err("Empty names aren't allowed".to_string())
     } else {
-        Some(format!("Hi! My name is {name}"))
+        Ok(format!("Hi! My name is {name}"))
     }
 }
 

exercises/13_error_handling/errors2.rs

@@ -21,7 +21,7 @@ fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let cost_per_item = 5;
 
     // TODO: Handle the error case as described above.
-    let qty = item_quantity.parse::<i32>();
+    let qty = item_quantity.parse::<i32>()?;
 
     Ok(qty * cost_per_item + processing_fee)
 }

exercises/13_error_handling/errors3.rs

@@ -15,7 +15,7 @@ fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
 
 // TODO: Fix the compiler error by changing the signature and body of the
 // `main` function.
-fn main() {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -24,8 +24,10 @@ fn main() {
 
     if cost > tokens {
         println!("You can't afford that many!");
+        Ok(())
     } else {
         tokens -= cost;
         println!("You now have {tokens} tokens.");
+        Ok(())
     }
 }

exercises/13_error_handling/errors4.rs

@@ -1,3 +1,5 @@
+use std::cmp::Ordering;
+
 #[derive(PartialEq, Debug)]
 enum CreationError {
     Negative,
@@ -11,7 +13,11 @@ impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<Self, CreationError> {
         // TODO: This function shouldn't always return an `Ok`.
         // Read the tests below to clarify what should be returned.
-        Ok(Self(value as u64))
+        match value.cmp(&0) {
+            Ordering::Less => Err(CreationError::Negative),
+            Ordering::Equal => Err(CreationError::Zero),
+            Ordering::Greater => Ok(Self(value as u64)),
+        }
     }
 }
 

exercises/13_error_handling/errors5.rs

@@ -48,7 +48,7 @@ impl PositiveNonzeroInteger {
 
 // TODO: Add the correct return type `Result<(), Box<dyn ???>>`. What can we
 // use to describe both errors? Is there a trait which both errors implement?
-fn main() {
+fn main() -> Result<(), Box<dyn Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);

exercises/13_error_handling/errors6.rs

@@ -34,7 +34,7 @@ impl PositiveNonzeroInteger {
     fn parse(s: &str) -> Result<Self, ParsePosNonzeroError> {
         // TODO: change this to return an appropriate error instead of panicking
         // when `parse()` returns an error.
-        let x: i64 = s.parse().unwrap();
+        let x: i64 = s.parse().map_err(ParsePosNonzeroError::ParseInt)?;
         Self::new(x).map_err(ParsePosNonzeroError::Creation)
     }
 }

exercises/14_generics/generics1.rs

@@ -6,7 +6,7 @@ fn main() {
     // TODO: Fix the compiler error by annotating the type of the vector
     // `Vec<T>`. Choose `T` as some integer type that can be created from
     // `u8` and `i8`.
-    let mut numbers = Vec::new();
+    let mut numbers: Vec<i16> = Vec::new();
 
     // Don't change the lines below.
     let n1: u8 = 42;

exercises/14_generics/generics2.rs

@@ -1,12 +1,12 @@
 // This powerful wrapper provides the ability to store a positive integer value.
 // TODO: Rewrite it using a generic so that it supports wrapping ANY type.
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
 // TODO: Adapt the struct's implementation to be generic over the wrapped value.
-impl Wrapper {
-    fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    fn new(value: T) -> Self {
         Wrapper { value }
     }
 }

exercises/15_traits/traits1.rs

@@ -6,6 +6,9 @@ trait AppendBar {
 
 impl AppendBar for String {
     // TODO: Implement `AppendBar` for the type `String`.
+    fn append_bar(self) -> Self {
+        self + &String::from("Bar")
+    }
 }
 
 fn main() {

exercises/15_traits/traits2.rs

@@ -4,6 +4,12 @@ trait AppendBar {
 
 // TODO: Implement the trait `AppendBar` for a vector of strings.
 // `append_bar` should push the string "Bar" into the vector.
+impl AppendBar for Vec<String> {
+    fn append_bar(mut self) -> Self {
+        self.push(String::from("Bar"));
+        self
+    }
+}
 
 fn main() {
     // You can optionally experiment here.

exercises/15_traits/traits3.rs

@@ -3,7 +3,9 @@ trait Licensed {
     // implementors like the two structs below can share that default behavior
     // without repeating the function.
     // The default license information should be the string "Default license".
-    fn licensing_info(&self) -> String;
+    fn licensing_info(&self) -> String {
+        String::from("Default license")
+    }
 }
 
 struct SomeSoftware {

exercises/15_traits/traits4.rs

@@ -11,7 +11,7 @@ impl Licensed for SomeSoftware {}
 impl Licensed for OtherSoftware {}
 
 // TODO: Fix the compiler error by only changing the signature of this function.
-fn compare_license_types(software1: ???, software2: ???) -> bool {
+fn compare_license_types(software1: impl Licensed, software2: impl Licensed) -> bool {
     software1.licensing_info() == software2.licensing_info()
 }
 

exercises/15_traits/traits5.rs

@@ -19,7 +19,7 @@ impl SomeTrait for OtherStruct {}
 impl OtherTrait for OtherStruct {}
 
 // TODO: Fix the compiler error by only changing the signature of this function.
-fn some_func(item: ???) -> bool {
+fn some_func(item: impl SomeTrait + OtherTrait) -> bool {
     item.some_function() && item.other_function()
 }
 

exercises/16_lifetimes/lifetimes1.rs

@@ -4,7 +4,7 @@
 // not own their own data. What if their owner goes out of scope?
 
 // TODO: Fix the compiler error by updating the function signature.
-fn longest(x: &str, y: &str) -> &str {
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
     } else {

exercises/16_lifetimes/lifetimes2.rs

@@ -15,6 +15,6 @@ fn main() {
     {
         let string2 = String::from("xyz");
         result = longest(&string1, &string2);
-    }
         println!("The longest string is '{result}'");
     }
+}

exercises/16_lifetimes/lifetimes3.rs

@@ -1,9 +1,9 @@
 // Lifetimes are also needed when structs hold references.
 
 // TODO: Fix the compiler errors about the struct.
-struct Book {
-    author: &str,
-    title: &str,
+struct Book<'a> {
+    author: &'a str,
+    title: &'a str,
 }
 
 fn main() {

exercises/17_tests/tests1.rs

@@ -13,11 +13,12 @@ fn main() {
 mod tests {
     // TODO: Import `is_even`. You can use a wildcard to import everything in
     // the outer module.
+    use super::*;
 
     #[test]
     fn you_can_assert() {
         // TODO: Test the function `is_even` with some values.
-        assert!();
-        assert!();
+        assert!(!is_even(1));
+        assert!(is_even(12));
     }
 }

exercises/17_tests/tests2.rs

@@ -15,9 +15,9 @@ mod tests {
     #[test]
     fn you_can_assert_eq() {
         // TODO: Test the function `power_of_2` with some values.
-        assert_eq!();
-        assert_eq!();
-        assert_eq!();
-        assert_eq!();
+        assert_eq!(power_of_2(2), 4);
+        assert_eq!(power_of_2(3), 8);
+        assert_eq!(power_of_2(10), 1024);
+        assert_eq!(power_of_2(42),  4398046511104);
     }
 }

exercises/17_tests/tests3.rs

@@ -29,13 +29,14 @@ mod tests {
         // TODO: This test should check if the rectangle has the size that we
         // pass to its constructor.
         let rect = Rectangle::new(10, 20);
-        assert_eq!(todo!(), 10); // Check width
-        assert_eq!(todo!(), 20); // Check height
+        assert_eq!(rect.width, 10); // Check width
+        assert_eq!(rect.height, 20); // Check height
     }
 
     // TODO: This test should check if the program panics when we try to create
     // a rectangle with negative width.
     #[test]
+    #[should_panic]
     fn negative_width() {
         let _rect = Rectangle::new(-10, 10);
     }
@@ -43,6 +44,7 @@ mod tests {
     // TODO: This test should check if the program panics when we try to create
     // a rectangle with negative height.
     #[test]
+    #[should_panic]
     fn negative_height() {
         let _rect = Rectangle::new(10, -10);
     }

exercises/18_iterators/iterators1.rs

@@ -13,13 +13,13 @@ mod tests {
         let my_fav_fruits = &["banana", "custard apple", "avocado", "peach", "raspberry"];
 
         // TODO: Create an iterator over the slice.
-        let mut fav_fruits_iterator = todo!();
+        let mut fav_fruits_iterator = my_fav_fruits.iter();
 
         assert_eq!(fav_fruits_iterator.next(), Some(&"banana"));
-        assert_eq!(fav_fruits_iterator.next(), todo!()); // TODO: Replace `todo!()`
+        assert_eq!(fav_fruits_iterator.next(), Some(&"custard apple")); // TODO: Replace `todo!()`
         assert_eq!(fav_fruits_iterator.next(), Some(&"avocado"));
-        assert_eq!(fav_fruits_iterator.next(), todo!()); // TODO: Replace `todo!()`
+        assert_eq!(fav_fruits_iterator.next(), Some(&"peach")); // TODO: Replace `todo!()`
         assert_eq!(fav_fruits_iterator.next(), Some(&"raspberry"));
-        assert_eq!(fav_fruits_iterator.next(), todo!()); // TODO: Replace `todo!()`
+        assert_eq!(fav_fruits_iterator.next(), None); // TODO: Replace `todo!()`
     }
 }

exercises/18_iterators/iterators2.rs

@@ -1,13 +1,15 @@
 // In this exercise, you'll learn some of the unique advantages that iterators
 // can offer.
 
+// I failed.
+
 // TODO: Complete the `capitalize_first` function.
 // "hello" -> "Hello"
 fn capitalize_first(input: &str) -> String {
     let mut chars = input.chars();
     match chars.next() {
         None => String::new(),
-        Some(first) => todo!(),
+        Some(first) => first.to_uppercase().to_string() + chars.as_str(),
     }
 }
 
@@ -16,6 +18,7 @@ fn capitalize_first(input: &str) -> String {
 // ["hello", "world"] -> ["Hello", "World"]
 fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
     // ???
+    words.iter().map(|word| capitalize_first(word)).collect()
 }
 
 // TODO: Apply the `capitalize_first` function again to a slice of string
@@ -23,6 +26,7 @@ fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
 // ["hello", " ", "world"] -> "Hello World"
 fn capitalize_words_string(words: &[&str]) -> String {
     // ???
+    words.iter().map(|word| capitalize_first(word)).collect()
 }
 
 fn main() {

exercises/18_iterators/iterators3.rs

@@ -11,21 +11,31 @@ enum DivisionError {
 // TODO: Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 fn divide(a: i64, b: i64) -> Result<i64, DivisionError> {
-    todo!();
+    if b == 0 {
+        Err(DivisionError::DivideByZero)
+    } else if b == -1 && a == i64::MIN {
+        Err(DivisionError::IntegerOverflow)
+    } else if a % b == 0 {
+        Ok(a / b)
+    } else {
+        Err(DivisionError::NotDivisible)
+    }
 }
 
 // TODO: Add the correct return type and complete the function body.
 // Desired output: `Ok([1, 11, 1426, 3])`
-fn result_with_list() {
+fn result_with_list() -> Result<Vec<i64>, DivisionError> {
     let numbers = [27, 297, 38502, 81];
     let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    division_results.collect()
 }
 
 // TODO: Add the correct return type and complete the function body.
 // Desired output: `[Ok(1), Ok(11), Ok(1426), Ok(3)]`
-fn list_of_results() {
+fn list_of_results() -> Vec<Result<i64, DivisionError>> {
     let numbers = [27, 297, 38502, 81];
     let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    division_results.collect()
 }
 
 fn main() {

exercises/18_iterators/iterators4.rs

@@ -10,6 +10,8 @@ fn factorial(num: u64) -> u64 {
     // - additional variables
     // For an extra challenge, don't use:
     // - recursion
+
+    (1..=num).product()
 }
 
 fn main() {

exercises/quizzes/quiz3.rs

@@ -12,18 +12,18 @@
 // block to support alphabetical report cards in addition to numerical ones.
 
 // TODO: Adjust the struct as described above.
-struct ReportCard {
-    grade: f32,
+struct ReportCard<T> {
+    grade: T,
     student_name: String,
     student_age: u8,
 }
 
 // TODO: Adjust the impl block as described above.
-impl ReportCard {
+impl<T: std::fmt::Display> ReportCard<T> {
     fn print(&self) -> String {
         format!(
             "{} ({}) - achieved a grade of {}",
-            &self.student_name, &self.student_age, &self.grade,
+            self.student_name, self.student_age, self.grade,
         )
     }
 }