結構話化程式碼容易添加新的函式 而不需要變動已有的資料結構
而物件導向得程式碼則是容易添加新的類別而不用變動已有的函式
以下是結構化的程式碼
class SalaryCalculator
{
public double Calculate(string person)
{
if (person.Equals("boss"))
{
return 500 * 22 * 24;
}
else if (person.Equals("DayWorker"))
{
return 200 * 22 * 24;
}
else if (person.Equals("partTime"))
{
return 100 * 22 * 24;
}
throw new NullReferenceException();
}
}
class Program
{
static void Main(string[] args)
{
SalaryCalculator calculator = new SalaryCalculator();
Console.WriteLine(calculator.Calculate("boss"));
Console.ReadLine();
}
}
是蠻容易而且不會變動到已有的結構但是如果要新增一個
NightWorker (夜班) 人員的薪資 就是必要更改現有的函式
class SalaryCalculator
{
private int workHours = 24;
public void SetWorkHours (int workHours )
{
this.workHours = workHours ;
}
public double Calculate(string person)
{
if (person.Equals("boss"))
{
return 500 * 22 * workHours ;
}
else if (person.Equals("DayWorker"))
{
return 200 * 22 * workHours ;
}
else if (person.Equals("partTime"))
{
return 100 * 22 * workHours ;
}
else if (person.Equals("NightWorker"))
{
return 300 * 22 * workHours ;
}
throw new NullReferenceException();
}
}
接著我們看看 物件導向的程式
interface CalculatorBase
{
public double Calculate();
}
class BossSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public override double Calculate()
{
return 500 * 22 * workHours;
}
}
class DayWorkerSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public override double Calculate()
{
return 200 * 22 * workHours;
}
}
class partTimeSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public override double Calculate()
{
return 100 * 22 * workHours;
}
}
class Program
{
static void Main(string[] args)
{
//SalaryCalculator calculator = new SalaryCalculator();
CalculatorBase calculator = new BossSalaryCalculate();
Console.WriteLine(calculator.Calculate());
Console.ReadLine();
}
}
interface CalculatorBase
{
public double Calculate();
public void SetWorkHours(int workHours);
}
class BossSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public void SetWorkHours(int workHours)
{
this.workHours = workHours;
}
public double Calculate()
{
return 500 * 22 * workHours;
}
}
class DayWorkerSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public void SetWorkHours(int workHours)
{
this.workHours = workHours;
}
public double Calculate()
{
return 200 * 22 * workHours;
}
}
class partTimeSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public void SetWorkHours(int workHours)
{
this.workHours = workHours;
}
public double Calculate()
{
return 100 * 22 * workHours;
}
}
class NightWorkerSalaryCalculate : CalculatorBase
{
private int workHours = 8;
public void SetWorkHours(int workHours)
{
this.workHours = workHours;
}
public override double Calculate()
{
return 300 * 22 * workHours;
}
}
上面的程式使用了interface 將計算的方式分隔開來使我們在新增NightWorker的時候並不會更改到其他的class 但是當我們需要添加新的函式時反而造成了很大的困擾
必須針對每個class 實做SetWorkHours 當class一多 這樣是很痛苦的
所以必須觀察系統所需要的
若要增加worker的薪資計算的彈性 就要使用物件導向的設計
若要增加worker的函式功能的彈性 就要使用結構化的設計
