Reduce rectangle ambiguity

changed field names to `top_left` and `bottom_right`

Author: andymac-2

src/custom_types/structs.md

@@ -29,8 +29,10 @@ struct Point {
 // Structs can be reused as fields of another struct
 #[allow(dead_code)]
 struct Rectangle {
-    p1: Point,
-    p2: Point,
+    // A rectangle can be specified by where the top left and bottom right
+    // corners are in space.
+    top_left: Point,
+    bottom_right: Point,
 }
 
 fn main() {
@@ -44,23 +46,26 @@ fn main() {
 
 
     // Instantiate a `Point`
-    let point: Point = Point { x: 0.3, y: 0.4 };
+    let point: Point = Point { x: 10.3, y: 0.4 };
 
     // Access the fields of the point
     println!("point coordinates: ({}, {})", point.x, point.y);
 
-    // Make a new point by using struct update syntax to use the fields of our other one
-    let new_point = Point { x: 0.1, ..point };
-    // `new_point.y` will be the same as `point.y` because we used that field from `point`
-    println!("second point: ({}, {})", new_point.x, new_point.y);
+    // Make a new point by using struct update syntax to use the fields of our
+    // other one
+    let bottom_right = Point { x: 5.2, ..point };
+    
+    // `bottom_right.y` will be the same as `point.y` because we used that field
+    // from `point`
+    println!("second point: ({}, {})", bottom_right.x, bottom_right.y);
 
     // Destructure the point using a `let` binding
-    let Point { x: my_x, y: my_y } = point;
+    let Point { x: top_edge, y: left_edge } = point;
 
     let _rectangle = Rectangle {
         // struct instantiation is an expression too
-        p1: Point { x: my_y, y: my_x },
-        p2: point,
+        top_left: Point { x: left_edge, y: top_edge },
+        bottom_right: bottom_right,
     };
 
     // Instantiate a unit struct

src/std/box.md

@@ -18,10 +18,12 @@ struct Point {
     y: f64,
 }
 
+// A Rectangle can be specified by where its top left and bottom right 
+// corners are in space
 #[allow(dead_code)]
 struct Rectangle {
-    p1: Point,
-    p2: Point,
+    top_left: Point,
+    bottom_right: Point,
 }
 
 fn origin() -> Point {
@@ -38,14 +40,14 @@ fn main() {
     // Stack allocated variables
     let point: Point = origin();
     let rectangle: Rectangle = Rectangle {
-        p1: origin(),
-        p2: Point { x: 3.0, y: 4.0 }
+        top_left: origin(),
+        bottom_right: Point { x: 3.0, y: -4.0 }
     };
 
     // Heap allocated rectangle
     let boxed_rectangle: Box<Rectangle> = Box::new(Rectangle {
-        p1: origin(),
-        p2: origin()
+        top_left: origin(),
+        bottom_right: Point { x: 3.0, y: -4.0 },
     });
 
     // The output of functions can be boxed