saving more progress

REVISITS.md

@@ -23,4 +23,9 @@ return results to new Vec<i32> vector
 22) trait3 -> very important for understanding default implementation and overrides. Also reread this page: https://doc.rust-lang.org/book/ch10-02-traits.html#default-implementations. Answer also here: https://users.rust-lang.org/t/rustlings-traits3-rs-question/80742/3
 25) trait5 -> important to understand trait bounds with generics. Also be sure to understand the short format vs. clearer format and pros/cons
 26) Retake quiz3 for more traits+generics practice
+27) lifetimes1
+28) standard library types iterators2 -> VERY IMPORTANT to understand map, chain/chain::<Vec<String>>, join
+29) iterator4 to make sure you understand fold/rfold
+
+clippy conversions macros standard_library_types  threads
 

exercises/lifetimes/lifetimes1.rs

@@ -7,9 +7,7 @@
 //
 // Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-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/lifetimes/lifetimes2.rs

@@ -6,8 +6,6 @@
 //
 // Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
@@ -22,6 +20,7 @@ fn main() {
     {
         let string2 = String::from("xyz");
         result = longest(string1.as_str(), string2.as_str());
-    }
         println!("The longest string is '{}'", result);
     }
+    
+}

exercises/lifetimes/lifetimes3.rs

@@ -4,11 +4,9 @@
 //
 // Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-struct Book {
-    author: &str,
-    title: &str,
+struct Book<'a> {
+    author: &'a str,
+    title: &'a str,
 }
 
 fn main() {

exercises/standard_library_types/iterators1.rs

@@ -8,17 +8,15 @@
 //
 // Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main () {
     let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
 
-    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+    let mut my_iterable_fav_fruits = my_fav_fruits.iter();   // TODO: Step 1
 
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"custard apple"));     // TODO: Step 2
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"peach"));     // TODO: Step 3
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
+    assert_eq!(my_iterable_fav_fruits.next(), None);     // TODO: Step 4
 }

exercises/standard_library_types/iterators2.rs

@@ -3,8 +3,6 @@
 // can offer. Follow the steps to complete the exercise.
 // Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 // Step 1.
 // Complete the `capitalize_first` function.
 // "hello" -> "Hello"
@@ -12,7 +10,7 @@ pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
         None => String::new(),
-        Some(first) => ???,
+        Some(first) => first.to_uppercase().chain(c).collect(),
     }
 }
 
@@ -21,7 +19,7 @@ pub fn capitalize_first(input: &str) -> String {
 // Return a vector of strings.
 // ["hello", "world"] -> ["Hello", "World"]
 pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
-    vec![]
+    words.iter().map(|word| capitalize_first(word)).collect()
 }
 
 // Step 3.
@@ -29,7 +27,7 @@ pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
 // Return a single string.
 // ["hello", " ", "world"] -> "Hello World"
 pub fn capitalize_words_string(words: &[&str]) -> String {
-    String::new()
+    capitalize_words_vector(words).join("")
 }
 
 #[cfg(test)]

exercises/standard_library_types/iterators3.rs

@@ -6,8 +6,6 @@
 //    list_of_results functions.
 // Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
     NotDivisible(NotDivisibleError),
@@ -23,21 +21,30 @@ pub struct NotDivisibleError {
 // Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
-    todo!();
+    if b == 0 {
+        return Err(DivisionError::DivideByZero);
+    }
+
+    match a%b{
+        0 => Ok(a/b),
+        _ => Err(DivisionError::NotDivisible(NotDivisibleError{dividend:a, divisor:b}))
+    }
 }
 
 // Complete the function and return a value of the correct type so the test passes.
 // Desired output: Ok([1, 11, 1426, 3])
-fn result_with_list() -> () {
+fn result_with_list() -> Result<Vec<i32>, DivisionError> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Vec<i32> = numbers.into_iter().map(|n| divide(n, 27).unwrap()).collect();
+    Ok(division_results)
 }
 
 // Complete the function and return a value of the correct type so the test passes.
 // Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
-fn list_of_results() -> () {
+fn list_of_results() -> Vec<Result<i32, DivisionError>> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Vec<Result<i32, DivisionError>> = numbers.into_iter().map(|n| divide(n, 27)).collect();
+    division_results
 }
 
 #[cfg(test)]

exercises/standard_library_types/iterators4.rs

@@ -1,8 +1,6 @@
 // iterators4.rs
 // Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub fn factorial(num: u64) -> u64 {
     // Complete this function to return the factorial of num
     // Do not use:
@@ -13,6 +11,7 @@ pub fn factorial(num: u64) -> u64 {
     // For an extra challenge, don't use:
     // - recursion
     // Execute `rustlings hint iterators4` for hints.
+    (1..=num).fold(1, |acc, x| acc * x)
 }
 
 #[cfg(test)]

exercises/tests/tests2.rs

@@ -3,12 +3,10 @@
 // pass! Make the test fail!
 // Execute `rustlings hint tests2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert_eq() {
-        assert_eq!();
+        assert_eq!("some words here", "some words here");
     }
 }

exercises/tests/tests3.rs

@@ -4,7 +4,6 @@
 // we expect to get when we call `is_even(5)`.
 // Execute `rustlings hint tests3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
@@ -16,11 +15,11 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(is_even(10));
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        assert_eq!(false, is_even(5));
     }
 }