20.策略者模式(Stragety Pattern)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication3
{
/// <summary>
/// 策略模式是针对一组算法，将每个算法封装到具有公共接口的独立的类中，
/// 从而使它们可以相互替换。策略模式使得算法可以在不影响到客户端的情况下发生变化。
/// </summary>
class Program
{
static void Main(string[] args)
{
// 个人所得税方式
InterestOperation operation = new InterestOperation(new PersonalTaxStrategy());
Console.WriteLine("个人支付的税为：{0}", operation.GetTax(5000.00));

// 企业所得税
operation = new InterestOperation(new EnterpriseTaxStrategy());
Console.WriteLine("企业支付的税为：{0}", operation.GetTax(50000.00));
Console.Read();
}
}

// 所得税计算策略
public interface ITaxStragety
{
double CalculateTax(double income);
}

// 个人所得税
public class PersonalTaxStrategy : ITaxStragety
{
public double CalculateTax(double income)
{
return income * 0.12;
}
}

// 企业所得税
public class EnterpriseTaxStrategy : ITaxStragety
{
public double CalculateTax(double income)
{
return (income - 3500) > 0 ? (income - 3500) * 0.045 : 0.0;
}
}

/// <summary>
/// 选择方法
/// </summary>
public class InterestOperation
{
private ITaxStragety m_strategy;
public InterestOperation(ITaxStragety strategy)
{
this.m_strategy = strategy;
}

public double GetTax(double income)
{
return m_strategy.CalculateTax(income);
}
}
}