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

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1		-```
	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	+ struct Square {
	11	+ length float
	12	+ }
	13	+
	14	+ struct Circle {
	15	+ radius float
	16	+ }
	17	+
	18	+ function Circumference(g Object) float {
	19	+ switch type(g):
	20	+ case Square:
	21	+ return 4 * g.length
	22	+ case Circle:
	23	+ return 2 * PI * g.radius
	24	+ }
	25	+
	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.
	28	+
	29	+####
	30	+
	31	+#### Object-Oriented Style
	32	+
	33	+ interface GeometricObject {
	34	+ Circumference() float
	35	+ }
	36	+
	37	+ class Square implements GeometricObject {
	38	+ length float
	39	+
	40	+ constructor(length float) {
	41	+ this.length = length
	42	+ }
	43	+
	44	+ func Circumference() float {
	45	+ return 4 * this.length
	46	+ }
	47	+ }
	48	+
	49	+ class Circle implements GeometricObject {
	50	+ radius float
	51	+
	52	+ constructor(radius float) {
	53	+ this.radius = radius
	54	+ }
	55	+
	56	+ func Circumference() float {
	57	+ return 2 * PI * this.radius
	58	+ }
	59	+ }