typeVariantsDemo in Swift

typeVariantsDemo.swift

// the Swift direct equivalent of the F# gist https://gist.github.com/AndyDentFree/46ac476a31b07d103a03

import Darwin
enum Shape {
  case Circle (radius:Double)
  case Rectangle (width:Double, height:Double)
  case Triangle (tbase:Double, height:Double)
}

func area(shape:Shape) -> Double {
  switch shape {
    case .Circle(let radius): return M_PI * radius * radius
    case .Rectangle (let width, let height): return width * height
    case .Triangle (let tbase, let height): return 0.5 * tbase * height
  }
}

let cshape = Shape.Circle(radius:10.0)
println("Circle Area: %f", area(cshape))

let rshape = Shape.Rectangle(width:3.0, height:7.0)
println("Rect Area: %f", area(rshape))

let tshape = Shape.Triangle(tbase:3.0, height:7.0)
println("Triangle Area: %f", area(tshape))