状态模式

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

namespace Club
{
    class Program
    {
        static void Main(string[] args)
        {
            Account account = new Account("Tom", 100);
            Console.WriteLine("Already!");
            Console.WriteLine("Name:{0}", account.Owner);
            Console.WriteLine("Initial:{0}", account.Balance);
            Console.WriteLine("-----------------------------------------");

            account.Deposit(100);
            Console.WriteLine("-----------------------------------------");

            account.Cost(300);
            Console.WriteLine("-----------------------------------------");

            account.Deposit(1000);
            Console.WriteLine("-----------------------------------------");

            account.Cost(700);
            Console.WriteLine("-----------------------------------------");

            Console.ReadLine();
        }
    }
}
class Account
{
    public ClientState State { get; set; }
    public string Owner { get; set; }
    public double Balance { get; set; }

    public Account(string owner, double initialAmount)
    {
        Owner = owner;
        Balance = initialAmount;
        State = new VistorState(this);
    }

    public void SetBalance(double amount)
    {
        Balance = amount;
    }

    public void Deposit(double amount)
    {
        Console.WriteLine("Now,deposit {0}.", amount);
        State.Deposit(amount);
        Console.WriteLine("ClientState turn to {0}", State);
    }

    public void Cost(double amount)
    {
        Console.WriteLine("Now,Cost {0}.", amount);
        State.Cost(amount);
        Console.WriteLine("ClientState turn to {0}", State);
    }
}
abstract class ClientState
{
    protected Account Account;
    public abstract void Deposit(double amount);
    public abstract void Cost(double amount);
    public abstract void Check();
}
class VistorState : ClientState
{
    public VistorState(Account account)
    {
        Account = account;
    }

    public override void Deposit(double amount)
    {
        Account.Balance += amount;
        Console.WriteLine("Deposit {0} to {1},surplus of account have {2} affter deposit", amount, Account.Owner, Account.Balance);
        Check();
    }

    public override void Cost(double amount)
    {
        double newBalance = Account.Balance - amount;
        Account.Balance -= amount;
        Console.WriteLine("Cost {0} from {1},surplus of account have {2} affter cost", amount, Account.Owner, Account.Balance);
        Check();
    }
    public override void Check()
    {
        if (Account.Balance > 100 && Account.Balance < 1000)
        {
            Account.State = new MemberState(Account);
        }
        else if (Account.Balance >= 1000)
        {
            Account.State = new VIPState(Account);
        }
    }
}
class MemberState : ClientState
{
    public MemberState(Account account)
    {
        Account = account;
    }

    public override void Deposit(double amount)
    {
        Account.Balance += amount;
        Console.WriteLine("Deposit {0} to {1},surplus of account have {2} affter deposit", amount, Account.Owner, Account.Balance);
        Check();
    }

    public override void Cost(double amount)
    {
        double newBalance = Account.Balance - amount;
        Account.Balance -= amount;
        Console.WriteLine("Cost {0} from {1},surplus of account have {2} affter cost", amount, Account.Owner, Account.Balance);
        Check();
    }
    public override void Check()
    {
        if (Account.Balance > 0 && Account.Balance <= 100)
        {
            Account.State = new VistorState(Account);
        }
        else if (Account.Balance >= 1000)
        {
            Account.State = new VIPState(Account);
        }
    }
}
class VIPState : ClientState
{
    public VIPState(Account account)
    {
        Account = account;
    }

    public override void Deposit(double amount)
    {
        Account.Balance += amount;
        Console.WriteLine("Deposit {0} to {1},surplus of account have {2} affter deposit", amount, Account.Owner, Account.Balance);
        Check();
    }

    public override void Cost(double amount)
    {
        double newBalance = Account.Balance - amount;
        Account.Balance -= amount;
        Console.WriteLine("Cost {0} from {1},surplus of account have {2} affter cost", amount, Account.Owner, Account.Balance);
        Check();
    }
    public override void Check()
    {
        if (Account.Balance > 100 && Account.Balance < 1000)
        {
            Account.State = new MemberState(Account);
        }
        else if (Account.Balance > 0 && Account.Balance <= 100)
        {
            Account.State = new VistorState(Account);
        }
    }
}