feat(options): completed options

exercises/12_options/options1.rs

@@ -4,6 +4,14 @@
 // `hour_of_day` is higher than 23.
 fn maybe_ice_cream(hour_of_day: u16) -> Option<u16> {
     // TODO: Complete the function body.
+
+    if hour_of_day < 22 {
+        Some(5)
+    } else if hour_of_day <= 23 {
+        Some(0)
+    } else {
+        None
+    }
 }
 
 fn main() {
@@ -18,7 +26,7 @@ mod tests {
     fn raw_value() {
         // TODO: Fix this test. How do you get the value contained in the
         // Option?
-        let ice_creams = maybe_ice_cream(12);
+        let ice_creams = maybe_ice_cream(12).unwrap();
 
         assert_eq!(ice_creams, 5); // Don't change this line.
     }

exercises/12_options/options2.rs

@@ -10,8 +10,12 @@ mod tests {
         let optional_target = Some(target);
 
         // TODO: Make this an if-let statement whose value is `Some`.
-        word = optional_target {
-            assert_eq!(word, target);
+        //
+        // word = optional_target {
+        //     assert_eq!(word, target);
+        // }
+        if let Some(word) = optional_target {
+            assert_eq!(word, target)
         }
     }
 
@@ -29,7 +33,13 @@ mod tests {
         // TODO: Make this a while-let statement. Remember that `Vec::pop()`
         // adds another layer of `Option`. You can do nested pattern matching
         // in if-let and while-let statements.
-        integer = optional_integers.pop() {
+        //
+        // integer = optional_integers.pop() {
+        //     assert_eq!(integer, cursor);
+        //     cursor -= 1;
+        // }
+
+        while let Some(Some(integer)) = optional_integers.pop() {
             assert_eq!(integer, cursor);
             cursor -= 1;
         }

exercises/12_options/options3.rs

@@ -9,7 +9,9 @@ fn main() {
 
     // TODO: Fix the compiler error by adding something to this match statement.
     match optional_point {
-        Some(p) => println!("Coordinates are {},{}", p.x, p.y),
+        Some(ref p) => {
+            println!("Coordinates are {},{}", p.x, p.y)
+        }
         _ => panic!("No match!"),
     }