done till exercises/quiz3

exercises/generics/generics1.rs

@@ -3,9 +3,22 @@
 
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// ChatGPT
+// Vec<_> is a shorthand syntax in Rust for declaring a vector with the element type left unspecified.
+
+// In Rust, a vector is a dynamically resizable array that allows you to store and manipulate a collection of elements. When declaring a vector, you typically specify the element type that the vector will contain. For example, to create a vector of integers, you would declare it as Vec<i32>.
+
+// However, if you want to declare a vector without specifying the element type, you can use the underscore (_) as a placeholder. This is useful when you want the compiler to infer the element type based on the values you insert into the vector.
+
+// For example, the following code creates a vector of integers and inserts the values 1, 2, and 3 into it:
+
+// let v: Vec<_> = vec![1, 2, 3];
+// Here, the underscore allows the compiler to infer that the vector contains integers. If you were to remove the underscore, you would have to explicitly specify the element type as i32:
+
+// let v: Vec<i32> = vec![1, 2, 3];
 
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<_> = Vec::new();
+    // let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }

exercises/generics/generics2.rs

@@ -3,14 +3,12 @@
 
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
-impl Wrapper {
-    pub fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    pub fn new(value: T) -> Self {
         Wrapper { value }
     }
 }

exercises/traits/README.md

@@ -7,13 +7,13 @@ Data types can implement traits. To do so, the methods making up the trait are d
 In this way, traits are somewhat similar to Java interfaces and C++ abstract classes.
 
 Some additional common Rust traits include:
+
 - `Clone` (the `clone` method)
 - `Display` (which allows formatted display via `{}`)
 - `Debug` (which allows formatted display via `{:?}`)
 
 Because traits indicate shared behavior between data types, they are useful when writing generics.
 
-
 ## Further information
 
 - [Traits](https://doc.rust-lang.org/book/ch10-02-traits.html)

exercises/traits/traits1.rs

@@ -9,14 +9,15 @@
 // implementing this trait.
 // Execute `rustlings hint traits1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 impl AppendBar for String {
     // TODO: Implement `AppendBar` for type `String`.
+    fn append_bar(self) -> Self {
+        format!("{}{}", self, "Bar")
+    }
 }
 
 fn main() {

exercises/traits/traits2.rs

@@ -11,13 +11,19 @@
 // you can do this!
 // Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 // TODO: Implement trait `AppendBar` for a vector of strings.
+impl AppendBar for Vec<String> {
+    // In other words, when a value is owned, its mutability is not part of the type, only the binding. When calling a function or implementing a trait, only the types have to match, not the patterns of the parameters
+    // When a value is moved, it doesn't matter for the method declaration whether or not it is mutated. An owned value can always be made mutable anyway: let mut x = x;
+    fn append_bar(mut self) -> Self {
+        self.push("Bar".into());
+        self
+    }
+}
 
 #[cfg(test)]
 mod tests {

exercises/traits/traits3.rs

@@ -7,10 +7,10 @@
 // Consider what you can add to the Licensed trait.
 // Execute `rustlings hint traits3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub trait Licensed {
-    fn licensing_info(&self) -> String;
+    fn licensing_info(&self) -> String {
+        String::from("Some information")
+    }
 }
 
 struct SomeSoftware {

exercises/traits/traits4.rs

@@ -4,8 +4,6 @@
 // Don't change any line other than the marked one.
 // Execute `rustlings hint traits4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub trait Licensed {
     fn licensing_info(&self) -> String {
         "some information".to_string()
@@ -20,7 +18,11 @@ impl Licensed for SomeSoftware {}
 impl Licensed for OtherSoftware {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn compare_license_types(software: ??, software_two: ??) -> bool {
+fn compare_license_types<T, U>(software: T, software_two: U) -> bool
+where
+    T: Licensed,
+    U: Licensed,
+{
     software.licensing_info() == software_two.licensing_info()
 }
 

exercises/traits/traits5.rs

@@ -4,8 +4,6 @@
 // Don't change any line other than the marked one.
 // Execute `rustlings hint traits5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub trait SomeTrait {
     fn some_function(&self) -> bool {
         true
@@ -27,7 +25,7 @@ impl SomeTrait for OtherStruct {}
 impl OtherTrait for OtherStruct {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn some_func(item: ??) -> bool {
+fn some_func(item: impl SomeTrait + OtherTrait) -> bool {
     item.some_function() && item.other_function()
 }