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	+ type Square struct {
13	13	length float
14	14	}
15	15
16		- class Circle implements GeometricObject {
	14	+ type Circle struct {
17	17	radius float
18	18	}
19	19
20		- function Circumference(g GeometricObject) float {
	18	+ func Circumference(g Object) float {
21	21	switch type(g):
22	22	case Square:
23	23	return 4 * g.length
...	...	@@ -25,8 +25,7 @@
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.
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 here is that data structures are easy to extend with functions and hard to extend with data type, and objects are easy to extend with other objects but hard to extend with functionality.
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.