Got through semantics, types, structs

exercises/move_semantics/move_semantics1.rs

@@ -1,12 +1,11 @@
 // move_semantics1.rs
 // Make me compile! Execute `rustlings hint move_semantics1` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
 
-    let vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(vec0); // We need mut because we're modifying vec1 in line 13
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 

exercises/move_semantics/move_semantics2.rs

@@ -1,13 +1,10 @@
 // move_semantics2.rs
 // Make me compile without changing line 13!
 // Execute `rustlings hint move_semantics2` for hints :)
-
-// I AM NOT DONE
-
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new(); 
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(&mut vec0); // We need to set line 5 to mutable, so we can mutably borrow vec0, this allows us to use vec.push in our function below
 
     // Do not change the following line!
     println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
@@ -17,12 +14,13 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: &mut Vec<i32>) -> Vec<i32> { 
-    let mut vec = vec;
+    //here we need &mut because our input vectors are mutable
+    let vec = vec;
 
     vec.push(22);
     vec.push(44);
     vec.push(66);
 
-    vec
+    vec.to_vec() // we need to transform vec into an immutable (type Vec not &Vec, see function defintion if you're still confused)
-}
+}

exercises/move_semantics/move_semantics3.rs

@@ -3,12 +3,12 @@
 // (no lines with multiple semicolons necessary!)
 // Execute `rustlings hint move_semantics3` for hints :)
 
-// I AM NOT DONE
+// Not entirely sure how this differs from move_semantics2.rs ...
 
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(&mut vec0);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -17,10 +17,10 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: &mut Vec<i32>) -> Vec<i32> {
     vec.push(22);
     vec.push(44);
     vec.push(66);
 
-    vec
+    vec.to_vec()
 }

exercises/move_semantics/move_semantics4.rs

@@ -4,12 +4,11 @@
 // freshly created vector from fill_vec to its caller.
 // Execute `rustlings hint move_semantics4` for hints!
 
-// I AM NOT DONE
+// Hopefully what I did is clear for posterity.
 
 fn main() {
-    let vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec();
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -20,7 +19,7 @@ fn main() {
 
 // `fill_vec()` no longer takes `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec = Vec::new();
 
     vec.push(22);
     vec.push(44);

exercises/move_semantics/move_semantics5.rs

@@ -3,13 +3,12 @@
 // adding, changing or removing any of them.
 // Execute `rustlings hint move_semantics5` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let mut x = 100;
     let y = &mut x;
+    *y += 100; // This works because otherwise we'd be borrowing something twice, without doing anything with it!
     let z = &mut x;
-    *y += 100;
     *z += 1000;
     assert_eq!(x, 1200);
 }

exercises/primitive_types/primitive_types1.rs

@@ -2,7 +2,6 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
-// I AM NOT DONE
 
 fn main() {
     // Booleans (`bool`)
@@ -12,7 +11,7 @@ fn main() {
         println!("Good morning!");
     }
 
-    let // Finish the rest of this line like the example! Or make it be false!
+    let is_evening = false;// Finish the rest of this line like the example! Or make it be false!
     if is_evening {
         println!("Good evening!");
     }

exercises/primitive_types/primitive_types2.rs

@@ -2,7 +2,6 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
-// I AM NOT DONE
 
 fn main() {
     // Characters (`char`)
@@ -16,7 +15,7 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
+    let your_character = '3'; // Finish this line like the example! What's your favorite character?
     // Try a letter, try a number, try a special character, try a character
     // from a different language than your own, try an emoji!
     if your_character.is_alphabetic() {

exercises/primitive_types/primitive_types3.rs

@@ -2,14 +2,13 @@
 // Create an array with at least 100 elements in it where the ??? is.
 // Execute `rustlings hint primitive_types3` for hints!
 
-// I AM NOT DONE
 
 fn main() {
-    let a = ???
+    let a = [1,2,3]; // This is the "array" type in Rust
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");
     } else {
         println!("Meh, I eat arrays like that for breakfast.");
     }
-}
+}

exercises/primitive_types/primitive_types4.rs

@@ -2,13 +2,12 @@
 // Get a slice out of Array a where the ??? is so that the test passes.
 // Execute `rustlings hint primitive_types4` for hints!!
 
-// I AM NOT DONE
 
 #[test]
 fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
 
-    let nice_slice = ???
+    let nice_slice = &a[1..4]; // this is how you slice arrays, much like slicing python lists, but you have to borrow the variable first, and it goes &array[i..n] and you get values from i to n-1.
 
     assert_eq!([2, 3, 4], nice_slice)
 }

exercises/primitive_types/primitive_types5.rs

@@ -2,11 +2,10 @@
 // Destructure the `cat` tuple so that the println will work.
 // Execute `rustlings hint primitive_types5` for hints!
 
-// I AM NOT DONE
 
 fn main() {
     let cat = ("Furry McFurson", 3.5);
-    let /* your pattern here */ = cat;
+    let (name,age) = cat; // This is like python, but you need parentheses 
 
     println!("{} is {} years old.", name, age);
 }

exercises/primitive_types/primitive_types6.rs

@@ -3,13 +3,12 @@
 // You can put the expression for the second element where ??? is so that the test passes.
 // Execute `rustlings hint primitive_types6` for hints!
 
-// I AM NOT DONE
 
 #[test]
 fn indexing_tuple() {
     let numbers = (1, 2, 3);
     // Replace below ??? with the tuple indexing syntax.
-    let second = ???;
+    let second = numbers.1; // This is pretty interesting, and a great example of where Rust differs strongly from python. I had guessed the answer was &numbers[1], but the compiler corrected me!
 
     assert_eq!(2, second,
         "This is not the 2nd number in the tuple!")

exercises/structs/structs1.rs

@@ -1,17 +1,17 @@
 // structs1.rs
 // Address all the TODOs to make the tests pass!
 
-// I AM NOT DONE
 
 struct ColorClassicStruct {
     // TODO: Something goes here
+    name: String,
+    hex: String,
 }
 
-struct ColorTupleStruct(/* TODO: Something goes here */);
+struct ColorTupleStruct(String, String);
 
 #[derive(Debug)]
 struct UnitStruct;
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -19,7 +19,10 @@ mod tests {
     #[test]
     fn classic_c_structs() {
         // TODO: Instantiate a classic c struct!
-        // let green =
+        let green = ColorClassicStruct {
+            name: String::from("green"),
+            hex: String::from("#00FF00"),
+        };
 
         assert_eq!(green.name, "green");
         assert_eq!(green.hex, "#00FF00");
@@ -28,7 +31,7 @@ mod tests {
     #[test]
     fn tuple_structs() {
         // TODO: Instantiate a tuple struct!
-        // let green =
+        let green = ColorTupleStruct(String::from("green"),String::from("#00FF00"));
 
         assert_eq!(green.0, "green");
         assert_eq!(green.1, "#00FF00");
@@ -37,7 +40,7 @@ mod tests {
     #[test]
     fn unit_structs() {
         // TODO: Instantiate a unit struct!
-        // let unit_struct =
+        let unit_struct = UnitStruct ; // Woah, so this is pulling UnitStruct as a string, and if I add parameters, you'd see them here, too! 
         let message = format!("{:?}s are fun!", unit_struct);
 
         assert_eq!(message, "UnitStructs are fun!");

exercises/structs/structs2.rs

@@ -1,7 +1,6 @@
 // structs2.rs
 // Address all the TODOs to make the tests pass!
 
-// I AM NOT DONE
 
 #[derive(Debug)]
 struct Order {
@@ -34,7 +33,9 @@ mod tests {
     fn your_order() {
         let order_template = create_order_template();
         // TODO: Create your own order using the update syntax and template above!
-        // let your_order =
+        let mut your_order = create_order_template();
+        your_order.name = String::from("Hacker in Rust");
+        your_order.count = 1;
         assert_eq!(your_order.name, "Hacker in Rust");
         assert_eq!(your_order.year, order_template.year);
         assert_eq!(your_order.made_by_phone, order_template.made_by_phone);

exercises/structs/structs3.rs

@@ -4,7 +4,6 @@
 // Make the code compile and the tests pass!
 // If you have issues execute `rustlings hint structs3`
 
-// I AM NOT DONE
 
 #[derive(Debug)]
 struct Package {
@@ -16,7 +15,7 @@ struct Package {
 impl Package {
     fn new(sender_country: String, recipient_country: String, weight_in_grams: i32) -> Package {
         if weight_in_grams <= 0 {
-            // panic statement goes here...
+            panic!("The weight {} is not possible!",weight_in_grams) 
         } else {
             Package {
                 sender_country,
@@ -26,12 +25,12 @@ impl Package {
         }
     }
 
-    fn is_international(&self) -> ??? {
+    fn is_international(&self) -> bool {
-        // Something goes here...
+        self.recipient_country != self.sender_country
     }
 
-    fn get_fees(&self, cents_per_gram: i32) -> ??? {
+    fn get_fees(&self, cents_per_gram: i32) -> i32 {
-        // Something goes here...
+        self.weight_in_grams*cents_per_gram
     }
 }