rustlings: move to rust/

1 files changed, 63 insertions, 0 deletions

diff --git a/rust/rustlings/exercises/18_iterators/iterators2.rs b/rust/rustlings/exercises/18_iterators/iterators2.rs
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+++ b/rust/rustlings/exercises/18_iterators/iterators2.rs
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+// In this exercise, you'll learn some of the unique advantages that iterators
+// can offer.
+
+// 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) => first.to_uppercase().to_string() + &input[1..],
+    }
+}
+
+// TODO: Apply the `capitalize_first` function to a slice of string slices.
+// Return a vector of strings.
+// ["hello", "world"] -> ["Hello", "World"]
+fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
+    let mut v = Vec::new();
+    for word in words {
+        if !word.trim().is_empty() {
+            v.push(capitalize_first(word));
+        }
+    }
+    v
+}
+
+// TODO: Apply the `capitalize_first` function again to a slice of string
+// slices. Return a single string.
+// ["hello", " ", "world"] -> "Hello World"
+fn capitalize_words_string(words: &[&str]) -> String {
+    capitalize_words_vector(words).join(" ")
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_success() {
+        assert_eq!(capitalize_first("hello"), "Hello");
+    }
+
+    #[test]
+    fn test_empty() {
+        assert_eq!(capitalize_first(""), "");
+    }
+
+    #[test]
+    fn test_iterate_string_vec() {
+        let words = vec!["hello", "world"];
+        assert_eq!(capitalize_words_vector(&words), ["Hello", "World"]);
+    }
+
+    #[test]
+    fn test_iterate_into_string() {
+        let words = vec!["hello", " ", "world"];
+        assert_eq!(capitalize_words_string(&words), "Hello World");
+    }
+}