透過此 多型(polymorphism)範例練習，來練習如何輕鬆達成薪資系統的三件事-實作範例。
1. 計算每個員工獎金紅利判定方法.
2. 計算每個員工需要繳的稅金利率.
3. 如何透過異質集合(Checking Thype) 來輕鬆計算所有員工的薪資總和.
Swift 實作
types.swift
main.swift
[Code程式區 - types.swift]
// 計算員工拿獎金
func getBouns(e : Employee) {
// 特例處理, 子孫類別先判對, 順序很重要
if e is Manager{
print("+1000")
let m1 : Manager = e as! Manager
print(m1.dept ?? "?")
} else if e is Employee {
print("+500")
}
}
// 計算員工需要繳的稅
func getTax(e : Employee) {
let totalY = e.salary * 14
if totalY < 800_000 {
print("Your tax is : 5%")
} else {
print("Your tax is : 12%")
}
}
class Employee {
var name : String?
var address : String?
var salary : Int = 20000 // 假設底薪28000-
func showInfo() {
print("\(name ?? "Noname") lives in \(address ?? "somewhere")")
}
}
class Manager: Employee {
var dept : String?
override func showInfo() {
print("\(name ?? "Noname") a manager of \(dept ?? "???"), Lives in \(address ?? "somewhere")")
}
}
class Engineer : Employee{
}
[Code程式區 - main.swift]
var m1 = Manager()
m1.name = "George"
m1.address = "Taipei"
m1.dept = "Engineer" // 繼承後, 客製化增加的
m1.salary = 60000
m1.showInfo()
// SWIFT-多型(polymorphism)範例測試, (Protocol 也會再一次碰到.)
var e : Employee = Manager()
e.name = "Frank"
e.address = "Tainan"
let m2 = e as? Manager // 將e轉化它的型別成為Manager
m2?.dept = "IT2"
e.showInfo() // 此時是呼叫執行實體Manager.showInfo()
var e1 : Employee = Employee()
e.name = "Frank"
e.address = "Tainan"
e.showInfo() // 此時是呼叫執行實體Manager.showInfo()
var e2 : Employee = Employee()
e.name = "Sam"
e.address = "Tainan"
e.showInfo() // 此時是呼叫執行實體Manager.showInfo()
var e3 : Engineer = Engineer()
e3.name = "George"
e3.address = "Taipei"
e3.showInfo()
// 多型應用-異質集合(Checking Thype) (抓出共通性來進行運作)
var employee : [Employee] = [m1, e1, e2, e3]
var total = 0
for e in employee {
total += e.salary
}
print("TOT: \(total)")
getTax(m1)
getTax(e1)
getTax(e2)
George Huang 烤蕃薯@Taipei 2016
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