Changes for page Code Example: Data Structure Style vs. Object Style
Last modified by chrisby on 2024/03/03 17:01
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... ... @@ -1,61 +1,70 @@ 1 -as d1 +### Use Cases 2 2 3 -``` 4 -type Square struct { 5 - length float 6 -} 3 +This example is intended to demonstrate the extensibility differences between data structures and objects by extending them with 7 7 8 -type Circle struct { 9 - length float 10 -} 5 +1. an Area() function (extending behavior) 6 +1. a rectangle type (extending data type) 11 11 12 -func Area(g GeometricObject) float { 13 - switch (g.type()): 14 - case Circle: 15 - return 16 - case Square: 17 - return ... 18 -} 8 +### Data Structure Style 19 19 20 -func Circumference(g GeometricObject) float { 21 - ... 22 -} 23 -``` 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 + } 24 24 25 -asd 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 26 27 -``` 28 -# Object-Oriented Style 31 +#### 29 29 30 -class Square { 31 - length float 33 +#### Object-Oriented Style 32 32 33 - constructor(length float) { 34 - this.length = length 35 - } 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 + } 36 36 37 - func Area() float { 38 - return this.length * this.length # Formula for square area: side^2 39 - } 63 +1. Adding a function Area() to GeometricObject Interface is hard since all classes implementing 64 +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. 40 40 41 - func Circumference() float { 42 - return 4 * this.length # Formula for square circumference: 4 * side 43 - } 44 -} 66 +### Conclusion 45 45 46 -class Circle { 47 - radius float 68 +asd 48 48 49 - constructor(radius float) { 50 - this.radius = radius 51 - } 52 - 53 - func Area() float { 54 - return 3.14159 * this.radius * this.radius # Formula for circle area: πr^2 55 - } 56 - 57 - func Circumference() float { 58 - return 2 * 3.14159 * this.radius # Formula for circle circumference: 2πr 59 - } 60 -} 61 -``` 70 +