Changes for page Code Example: Data Structure Style vs. Object Style

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1		-### Use Cases
2		-
3		-This example is intended to demonstrate the extensibility differences between data structures and objects by extending them with
4		-
5		-1. an Area() function (extending behavior)
6		-1. a rectangle type (extending data type)
7		-
8		-### Data Structure Style
9		-
10		- interface GeometricObject {}
11		-
12		- class Square implements GeometricObject {
13		- length float
14		- }
15		-
16		- class Circle implements GeometricObject {
17		- radius float
18		- }
19		-
20		- function Circumference(g GeometricObject) float {
21		- switch type(g):
22		- case Square:
23		- return 4 * g.length
24		- case Circle:
25		- return 2 * PI * g.radius
26		- }
27		-
28		-1. Adding an Area() function with a very similar anatomy to Circumference() is easy because it only requires adding new code.
29		-1. Adding a new datatype, Rectangle, is harder because it requires touching existing code, namely any functions like Circumference() or Area() that need to be enabled handle this datatype.
30		-
31		-####
32		-
33		-#### Object-Oriented Style
34		-
35		- interface GeometricObject {
36		- Circumference() float
37		- }
38		-
39		- class Square implements GeometricObject {
40		- length float
41		-
42		- constructor(length float) {
43		- this.length = length
44		- }
45		-
46		- func Circumference() float {
47		- return 4 * this.length
48		- }
49		- }
50		-
51		- class Circle implements GeometricObject {
52		- radius float
53		-
54		- constructor(radius float) {
55		- this.radius = radius
56		- }
57		-
58		- func Circumference() float {
59		- return 2 * PI * this.radius
60		- }
61		- }
62		-
63		-1. Adding a function Area() to the GeometricObject interface is hard because it requires touching existing code, namely extending all Square and Circle classes with the new function.
64		-1. Adding a new datatype, Rectangle, is easy because only new code is added, namely a Rectangle class.
65		-
66		-### Conclusion
67		-
68		-* The lesson learned here is that data structures are easy to extend with functions, and objects are easy to extend with data types.
69		-* Although the difference between the two styles may seem insignificant in this simplified example, it has serious implications in complex production codebases with multiple data types and behaviors.
	1	+```