feat: 🎸 added solutions for iterators exercises

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() {
-
-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

@@ -3,16 +3,18 @@
 // 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"
 pub fn capitalize_first(input: &str) -> String {
-    let mut c = input.chars();
+    let mut it = input.chars();
-    match c.next() {
+    match it.next() {
         None => String::new(),
-        Some(first) => ???,
+        Some(first) => {
+            let mut cap_str = first.to_uppercase().collect::<String>();
+            cap_str.push_str(&it.collect::<String>());
+            cap_str
+        }
     }
 }
 
@@ -21,7 +23,14 @@ 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![]
+    let mut result = Vec::<String>::new();
+
+    for word in words {
+        let capitalized = capitalize_first(*word);
+        result.push(capitalized.to_string());
+    }
+
+    result
 }
 
 // Step 3.
@@ -29,7 +38,15 @@ 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()
+    let mut it = words.iter();
+    let mut result = String::new();
+
+    while let Some(word) = it.next() {
+        let capitalized = capitalize_first(*word);
+        result.push_str(&capitalized);
+    }
+
+    result
 }
 
 #[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),
@@ -20,24 +18,39 @@ pub struct NotDivisibleError {
     divisor: i32,
 }
 
-// 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);
+    }
+
+    if a % b != 0 {
+        return Err(DivisionError::NotDivisible(NotDivisibleError {
+            dividend: a,
+            divisor: b,
+        }));
+    }
+
+    Ok(a / 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: Result<Vec<i32>, DivisionError> =
+        numbers.into_iter().map(|n| divide(n, 27)).collect();
+
+    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 +11,13 @@ pub fn factorial(num: u64) -> u64 {
     // For an extra challenge, don't use:
     // - recursion
     // Execute `rustlings hint iterators4` for hints.
+    if num == 0 {
+        return 1;
+    } else if num == 1 {
+        return 1;
+    } else {
+        return num * factorial(num - 1);
+    }
 }
 
 #[cfg(test)]

exercises/standard_library_types/iterators5.rs

@@ -10,8 +10,6 @@
 //
 // Make the code compile and the tests pass.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -34,7 +32,14 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
 fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
     // map is a hashmap with String keys and Progress values.
     // map = { "variables1": Complete, "from_str": None, ... }
-    todo!();
+    let mut it = map.iter();
+    let mut count = 0;
+    while let Some((_, val)) = it.next() {
+        if val == &value {
+            count += 1;
+        }
+    }
+    count
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -53,7 +58,17 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
-    todo!();
+    let mut it = collection.iter();
+    let mut count = 0;
+    while let Some(map) = it.next() {
+        let mut it = map.iter();
+        while let Some((_, val)) = it.next() {
+            if val == &value {
+                count += 1;
+            }
+        }
+    }
+    count
 }
 
 #[cfg(test)]