Wiki source code of Code Example: Data Structure Style vs. Object Style
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author | version | line-number | content |
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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 | type Square struct { | ||
11 | length float | ||
12 | } | ||
13 | |||
14 | type Circle struct { | ||
15 | radius float | ||
16 | } | ||
17 | |||
18 | func 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. | ||
27 | |||
28 | #### | ||
29 | |||
30 | #### Object-Oriented Style | ||
31 | |||
32 | interface GeometricObject { | ||
33 | Circumference() float | ||
34 | } | ||
35 | |||
36 | class Square implements GeometricObject { | ||
37 | length float | ||
38 | |||
39 | constructor(length float) { | ||
40 | this.length = length | ||
41 | } | ||
42 | |||
43 | func Circumference() float { | ||
44 | return 4 * this.length | ||
45 | } | ||
46 | } | ||
47 | |||
48 | class Circle implements GeometricObject { | ||
49 | radius float | ||
50 | |||
51 | constructor(radius float) { | ||
52 | this.radius = radius | ||
53 | } | ||
54 | |||
55 | func Circumference() float { | ||
56 | return 2 * PI * this.radius | ||
57 | } | ||
58 | } |