Rect area as method

rustbook/rectangles/src/main.rs

@@ -4,6 +4,12 @@ struct Rectangle {
     height: u32,
 }
 
+impl Rectangle {
+    fn area(&self) -> u32 {
+        self.width * self.height
+    }
+}
+
 fn main() {
     let rect1 = Rectangle { width: 30, height: 50 };
 
@@ -11,10 +17,6 @@ fn main() {
 
     println!(
         "The area of the rectangle is {} square pixels.",
-        area(&rect1)
+        rect1.area()
     );
 }
-
-fn area(rectangle: &Rectangle) -> u32 {
-    rectangle.width * rectangle.height
-}