I'll cross this bridge when I get there

ch5/method_syntax/src/main.rs

@@ -16,6 +16,17 @@ impl Rectangle {
     fn width(&self) -> bool {
         self.width > 0
     }
+
+    fn set_width(&mut self, width: u32) {
+        self.width = width;
+    }
+
+    fn max(self, other: Rectangle) -> Rectangle {
+        Rectangle {
+            width: self.width.max(other.width),
+            height: self.height.max(other.height),
+        }
+    }
 }
 
 fn main() {
@@ -33,6 +44,22 @@ fn main() {
         println!("rect has a nonzero width; it is: {}", rect1.width);
     }
 
-    // stopped here:
+    // need mutable reference to set width
-    // https://rust-book.cs.brown.edu/ch05-03-method-syntax.html#methods-and-ownership
+    let rect0 = Rectangle {
+        width: 0,
+        height: 0,
+    };
+
+    println!("{}", rect0.area());
+    let other_rect = Rectangle {
+        width: 1,
+        height: 1,
+    };
+    let max_rect = rect0.max(other_rect); // can't use rect0 after passing to max
+
+    let mut mut_rect = Rectangle {
+        width: 0,
+        height: 0,
+    };
+    mut_rect.set_width(9);
 }