Data update

Task/Null-object/Rust/null-object.rs

@@ -0,0 +1,20 @@
+// If an option may return null - or nothing - in Rust, it's wrapped
+// in an Optional which may return either the type of object specified
+// in <> or None. We can check this using .is_some() and .is_none() on
+// the Option.
+
+fn check_number(num: &Option<u8>) {
+    if num.is_none() {
+        println!("Number is: None");
+    } else {
+        println!("Number is: {}", num.unwrap());
+    }
+}
+
+fn main() {
+    let mut possible_number: Option<u8> = None;
+    check_number(&possible_number);
+
+    possible_number = Some(31);
+    check_number(&possible_number);
+}