Adding options

exercises/options/options1.rs

@@ -3,7 +3,6 @@
 // Execute `rustlings hint options1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 // This function returns how much icecream there is left in the fridge.
 // If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
@@ -13,7 +12,9 @@ fn maybe_icecream(time_of_day: u16) -> Option<u16> {
     // value of 0 The Option output should gracefully handle cases where
     // time_of_day > 23.
     // TODO: Complete the function body - remember to return an Option!
-    ???
+    if time_of_day < 22 { Some(5) }
+    else if time_of_day >= 22 && time_of_day < 25 { Some(0) }
+    else { None }
 }
 
 #[cfg(test)]
@@ -33,7 +34,7 @@ mod tests {
     fn raw_value() {
         // TODO: Fix this test. How do you get at the value contained in the
         // Option?
-        let icecreams = maybe_icecream(12);
-        assert_eq!(icecreams, 5);
+        let icecreams = maybe_icecream(12).expect("No icecream");
+        assert_eq!(icecreams, 5u16);
     }
 }

exercises/options/options2.rs

@@ -3,7 +3,6 @@
 // Execute `rustlings hint options2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 #[cfg(test)]
 mod tests {
@@ -13,7 +12,7 @@ mod tests {
         let optional_target = Some(target);
 
         // TODO: Make this an if let statement whose value is "Some" type
-        word = optional_target {
+        if let Some(word) = optional_target {
             assert_eq!(word, target);
         }
     }
@@ -32,9 +31,11 @@ mod tests {
         // TODO: make this a while let statement - remember that vector.pop also
         // adds another layer of Option<T>. You can stack `Option<T>`s into
         // while let and if let.
-        integer = optional_integers.pop() {
-            assert_eq!(integer, cursor);
-            cursor -= 1;
+        while let Some(int) = optional_integers.pop() {
+            if let Some(integer) = int {
+                assert_eq!(integer, cursor);
+                cursor -= 1;
+            }
         }
 
         assert_eq!(cursor, 0);

exercises/options/options3.rs

@@ -3,7 +3,6 @@
 // Execute `rustlings hint options3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 struct Point {
     x: i32,
@@ -13,7 +12,7 @@ struct Point {
 fn main() {
     let y: Option<Point> = Some(Point { x: 100, y: 200 });
 
-    match y {
+    match &y {
         Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
         _ => panic!("no match!"),
     }