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

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...	...	@@ -7,17 +7,15 @@
7	7
8	8	### Data Structure Style
9	9
10		- interface GeometricObject {}
11		-
12		- class Square implements GeometricObject {
	10	+ struct Square {
13	13	length float
14	14	}
15	15
16		- class Circle implements GeometricObject {
	14	+ struct Circle {
17	17	radius float
18	18	}
19	19
20		- function Circumference(g GeometricObject) float {
	18	+ function Circumference(g Object) float {
21	21	switch type(g):
22	22	case Square:
23	23	return 4 * g.length
...	...	@@ -25,8 +25,8 @@
25	25	return 2 * PI * g.radius
26	26	}
27	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.
	26	+1. Adding a function Area() with the same anatomy as Circumference() is easy, since it only requires adding new code.
	27	+1. Adding a new datatype, Rectangle, is more difficult because it requires touching existing code, namely any functions like Circumference() or Area() that need to be enabled handle this datatype.
30	30
31	31	####
32	32
...	...	@@ -59,11 +59,3 @@
59	59	return 2 * PI * this.radius
60	60	}
61	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.