first snapshot of progress.

exercises/functions/functions1.rs

@@ -1,7 +1,7 @@
 // functions1.rs
 // Make me compile! Execute `rustlings hint functions1` for hints :)
 
-// I AM NOT DONE
+fn call_me () {}
 
 fn main() {
     call_me();

exercises/functions/functions2.rs

@@ -1,13 +1,12 @@
 // functions2.rs
 // Make me compile! Execute `rustlings hint functions2` for hints :)
 
-// I AM NOT DONE
-
 fn main() {
     call_me(3);
 }
 
-fn call_me(num) {
+// NOTE: It is interesting that the function is defined below main but main can still call this.
+fn call_me(num: i32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

exercises/functions/functions3.rs

@@ -1,10 +1,8 @@
 // functions3.rs
 // Make me compile! Execute `rustlings hint functions3` for hints :)
 
-// I AM NOT DONE
-
 fn main() {
-    call_me();
+    call_me(10);
 }
 
 fn call_me(num: i32) {

exercises/functions/functions4.rs

@@ -4,14 +4,12 @@
 // This store is having a sale where if the price is an even number, you get
 // 10 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
 
-// I AM NOT DONE
-
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> {
+fn sale_price(price: i32) -> i32 {
     if is_even(price) {
         price - 10
     } else {

exercises/functions/functions5.rs

@@ -1,13 +1,11 @@
 // functions5.rs
 // Make me compile! Execute `rustlings hint functions5` for hints :)
 
-// I AM NOT DONE
-
 fn main() {
     let answer = square(3);
     println!("The answer is {}", answer);
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }

exercises/if/if1.rs

@@ -1,13 +1,12 @@
 // if1.rs
 
-// I AM NOT DONE
-
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
     // - another function call
     // - additional variables
     // Execute `rustlings hint if1` for hints
+    if a >= b { a } else { b }
 }
 
 // Don't mind this for now :)

exercises/modules/modules1.rs

@@ -1,10 +1,9 @@
 // modules1.rs
 // Make me compile! Execute `rustlings hint modules1` for hints :)
 
-// I AM NOT DONE
 
 mod sausage_factory {
-    fn make_sausage() {
+    pub fn make_sausage() {
         println!("sausage!");
     }
 }

exercises/modules/modules2.rs

@@ -1,11 +1,10 @@
 // modules2.rs
 // Make me compile! Execute `rustlings hint modules2` for hints :)
 
-// I AM NOT DONE
-
 mod delicious_snacks {
-    use self::fruits::PEAR as fruit;
+    // Just like items, name bindings as a result of use is private by default.
-    use self::veggies::CUCUMBER as veggie;
+    pub use self::fruits::PEAR as fruit;
+    pub use self::veggies::CUCUMBER as veggie;
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";

exercises/primitive_types/primitive_types1.rs

@@ -2,8 +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 +10,7 @@ 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

@@ -2,8 +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 +14,8 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
+    // This is amazing; Rust handles Unicode so well; It even understands alphabets vs numbers in other languages; 
+    let your_character = 'అ'; // 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

@@ -2,10 +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 = ???
+    // Initialize the array to zeroes of size 100
+    // Copy trait needs to be implemented by the type. In this case its primitive type.
+    let a = [0; 100];
+    // Explicitly initialize each element
+    // let a = [0, 0, 0];
+    // let a: [Option<String>; 3] = [None; 3]; alternatively let a: [Option<String>; 3] = Default::default(); if string doesn't support copy trait.
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");

exercises/primitive_types/primitive_types4.rs

@@ -2,13 +2,14 @@
 // 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];
 
+    // XXX Reason you don't need to add '&' infront of the slice [2,3,4] is
+    // deref trait is implicit in the current context. 
+    // If we define a new data type and define our own deref trait, the same behavior can be expected.
     assert_eq!([2, 3, 4], nice_slice)
 }

exercises/primitive_types/primitive_types5.rs

@@ -2,11 +2,9 @@
 // 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;
 
     println!("{} is {} years old.", name, age);
 }

exercises/primitive_types/primitive_types6.rs

@@ -3,9 +3,7 @@
 // You can put this right into the `println!` where the ??? is.
 // Execute `rustlings hint primitive_types6` for hints!
 
-// I AM NOT DONE
-
 fn main() {
     let numbers = (1, 2, 3);
-    println!("The second number is {}", ???);
+    println!("The second number is {}", numbers.1);
 }

exercises/strings/strings1.rs

@@ -2,13 +2,12 @@
 // Make me compile without changing the function signature!
 // Execute `rustlings hint strings1` for hints ;)
 
-// I AM NOT DONE
-
 fn main() {
     let answer = current_favorite_color();
     println!("My current favorite color is {}", answer);
 }
 
 fn current_favorite_color() -> String {
-    "blue"
+    "blue".to_string()
+    //String::from("blue")
 }

exercises/strings/strings2.rs

@@ -2,11 +2,9 @@
 // Make me compile without changing the function signature!
 // Execute `rustlings hint strings2` for hints :)
 
-// I AM NOT DONE
-
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
-    if is_a_color_word(word) {
+    if is_a_color_word(&word) {
         println!("That is a color word I know!");
     } else {
         println!("That is not a color word I know.");

exercises/structs/structs1.rs

@@ -1,13 +1,12 @@
 // structs1.rs
 // Address all the TODOs to make the tests pass!
 
-// I AM NOT DONE
+struct ColorClassicStruct<'a> {
-
+    name: &'a str,
-struct ColorClassicStruct {
+    hex: &'a str,
-    // TODO: Something goes here
 }
 
-struct ColorTupleStruct(/* TODO: Something goes here */);
+struct ColorTupleStruct<'a> (&'a str, &'a str);
 
 #[derive(Debug)]
 struct UnitStruct;
@@ -18,8 +17,7 @@ mod tests {
 
     #[test]
     fn classic_c_structs() {
-        // TODO: Instantiate a classic c struct!
+        let green = ColorClassicStruct {name: "green", hex: "#00FF00"};
-        // let green =
 
         assert_eq!(green.name, "green");
         assert_eq!(green.hex, "#00FF00");
@@ -27,8 +25,7 @@ mod tests {
 
     #[test]
     fn tuple_structs() {
-        // TODO: Instantiate a tuple struct!
+        let green = ("green", "#00FF00");
-        // let green =
 
         assert_eq!(green.0, "green");
         assert_eq!(green.1, "#00FF00");
@@ -36,8 +33,7 @@ mod tests {
 
     #[test]
     fn unit_structs() {
-        // TODO: Instantiate a unit struct!
+        let unit_struct = UnitStruct;
-        // let unit_struct =
         let message = format!("{:?}s are fun!", unit_struct);
 
         assert_eq!(message, "UnitStructs are fun!");

exercises/structs/structs2.rs

@@ -2,8 +2,6 @@
 // Address all the TODOs to make the tests pass!
 // No hints, just do it!
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 struct Order {
     name: String,
@@ -35,7 +33,7 @@ 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 your_order = Order {name: String::from("Hacker in Rust"), count: 1, ..order_template};
         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/test1.rs

@@ -7,10 +7,11 @@
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the order amount. No hints this time!
 
-// I AM NOT DONE
-
 // Put your function here!
 // fn ..... {
+fn calculate_apple_price (order: u32) -> u32 {
+    if order > 40 { order } else { order * 2 }
+}
 
 // Don't modify this function!
 #[test]

exercises/test3.rs

@@ -7,8 +7,6 @@
 // we expect to get when we call `times_two` with a negative number.
 // No hints, you can do this :)
 
-// I AM NOT DONE
-
 pub fn times_two(num: i32) -> i32 {
     num * 2
 }
@@ -19,11 +17,12 @@ mod tests {
 
     #[test]
     fn returns_twice_of_positive_numbers() {
-        assert_eq!(times_two(4), ???);
+        assert_eq!(times_two(4), 8);
     }
 
     #[test]
     fn returns_twice_of_negative_numbers() {
         // TODO write an assert for `times_two(-4)`
+        assert_eq!(times_two(-4), -8);
     }
 }

exercises/tests/tests2.rs

@@ -2,12 +2,10 @@
 // This test has a problem with it -- make the test compile! Make the test
 // pass! Make the test fail! Execute `rustlings hint tests2` for hints :)
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert_eq() {
-        assert_eq!();
+        assert_eq!(1, 1);
     }
 }

exercises/tests/tests3.rs

@@ -4,8 +4,6 @@
 // we expect to get when we call `is_even(5)`.
 // Execute `rustlings hint tests3` for hints :)
 
-// I AM NOT DONE
-
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
@@ -16,6 +14,11 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(is_even(2));
+    }
+
+    #[test]
+    fn negative_test() {
+        assert!(!is_even(5));
     }
 }

exercises/variables/variables1.rs

@@ -6,9 +6,7 @@
 // even after you already figured it out. If you got everything working and
 // feel ready for the next exercise, remove the `I AM NOT DONE` comment below.
 
-// I AM NOT DONE
-
 fn main() {
-    x = 5;
+    let x = 5;
     println!("x has the value {}", x);
 }

exercises/variables/variables2.rs

@@ -1,10 +1,12 @@
 // variables2.rs
 // Make me compile! Execute the command `rustlings hint variables2` if you want a hint :)
 
-// I AM NOT DONE
-
 fn main() {
-    let x;
+    // Just specifying the type is not sufficient as Rust doesn't allow uninitalized variables to be used later.alloc
+    // Just specifying the value is fine as type is inferred,
+    // but if it doesn't match with the value being compared later, we get error. let x = 10.0;
+    // You can always specify both.
+    let x = 10;
     if x == 10 {
         println!("Ten!");
     } else {

exercises/variables/variables3.rs

@@ -1,10 +1,8 @@
 // variables3.rs
 // Make me compile! Execute the command `rustlings hint variables3` if you want a hint :)
 
-// I AM NOT DONE
-
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {}", x);
     x = 5;
     println!("Number {}", x);

exercises/variables/variables4.rs

@@ -1,9 +1,7 @@
 // variables4.rs
 // Make me compile! Execute the command `rustlings hint variables4` if you want a hint :)
 
-// I AM NOT DONE
-
 fn main() {
-    let x: i32;
+    let x: i32 = 42;
     println!("Number {}", x);
 }