added exercise

exercises/14_generics/generics3.rs

@@ -0,0 +1,35 @@
+// generics3.rs
+// Execute `rustlings hint generics3` or use the `hint` watch subcommand for a hint.
+
+// TODO Use your knowledge of generics to enchance the `stringify` function by only changing the signature.
+fn stringify(list: &[&str]) -> String {
+    let items_str = list
+        .iter()
+        .map(|e| e.to_string())
+        .collect::<Vec<String>>()
+        .join(", ");
+    format!("[{items_str}]")
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_str_on_list() {
+        let names_list = vec!["maria", "jacob", "kacper"];
+        let stringified = stringify(&names_list);
+        assert_eq!(stringified, "[maria, jacob, kacper]".to_string());
+    }
+
+    #[test]
+    fn store_numbers_on_list() {
+        let numbers_list = vec![1, 2, 3];
+        let stringified = stringify(&numbers_list);
+        assert_eq!(stringified, "[1, 2, 3]".to_string());
+    }
+}

rustlings-macros/info.toml

@@ -741,6 +741,20 @@ hint = """
 Related section in The Book:
 https://doc.rust-lang.org/book/ch10-01-syntax.html#in-method-definitions"""
 
+[[exercises]]
+name = "generics3"
+dir = "14_generics"
+hint = """
+Vectors in Rust use generics to create dynamically-sized arrays of any type.
+The stringify function takes a vector as an argument, but only accepts vectors that store the &str type.
+To allow the function to accept vectors that store any type, you can leverage your knowledge about generics.
+If you're unsure how to proceed, please refer to the Rust Book at:
+https://doc.rust-lang.org/book/ch10-01-syntax.html#in-function-definitions.
+
+*Please note that in `stringify` we want to use `.to_string()` on vector elements
+Refer to this: https://doc.rust-lang.org/book/ch10-02-traits.html
+"""
+
 # TRAITS
 
 [[exercises]]

solutions/14_generics/generics3.rs

@@ -0,0 +1,38 @@
+// generics3.rs
+// Execute `rustlings hint generics3` or use the `hint` watch subcommand for a hint.
+
+// Here we add generic in function declaration so function can work with different types
+fn stringify<T>(list: &Vec<T>) -> String 
+where
+    T: ToString // here we also specify that T needs to implement ToString trait so we can use .to_string() on the vetor elements
+{
+    let items_str = list
+        .iter()
+        .map(|e| e.to_string())
+        .collect::<Vec<String>>()
+        .join(", ");
+    format!("[{items_str}]")
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_str_on_list() {
+        let names_list = vec!["maria", "jacob", "kacper"];
+        let stringified = stringify(&names_list);
+        assert_eq!(stringified, "[maria, jacob, kacper]".to_string());
+    }
+
+    #[test]
+    fn store_numbers_on_list() {
+        let numbers_list = vec![1, 2, 3];
+        let stringified = stringify(&numbers_list);
+        assert_eq!(stringified, "[1, 2, 3]".to_string());
+    }
+}