//eg:银行账户存钱取钱
//  账户类：
//  -balance()  余额
//  -deposit()  存钱
//  -withdraw() 取钱
//  -transfer(to:账户,amount:Dobule)转账

package Test1104
//银行账户

class BankAccount(private var balance:Int){
  def showMoney():Unit ={
    println(s"现在的余额是:${balance}")
  }
  def deposit(money:Int):Unit ={
    balance += money
  }
  def withdraw(money:Int):Unit ={
    if(money <= balance)
      balance -= money
  }
  //转账
  def transfer(to:BankAccount,money:Int):Unit = {
    //A --200-->B
    //A 减少 B 增加
  }
}

object Test11041 {
  def main(args: Array[String]): Unit = {
    var xiaoming = new BankAccount(0)
    var xiaohua = new BankAccount(100)
    //存入200
    xiaohua.deposit(200)
    //取出150
    xiaohua.withdraw(1500)

    //转账给小明
    xiaohua.transfer(100)

    xiaohua.showMoney()
    xiaoming.showMoney()

//    println(xiaohua.balance)


  }
}

package Test1104
//银行账户

//private[this]:这个属性，只能在当前对象上使用！
class BankAccount(private var balance:Int){
  def showMoney():Unit ={
    println(s"现在的余额是:${balance}")
  }
  def deposit(money:Int):Unit ={
    balance += money
  }
  def withdraw(money:Int):Unit ={
    if(money <= balance)
      balance -= money
  }
  
//  如何实现
  //转账：把当前的账户的余额全部转出 money 给 to 这个账户
  def transfer(to:BankAccount,money:Int):Unit = {
    //A --200-->B
    //A 减少 B 增加
    if(money <= balance){
      //把自己减少
      to.balance -= money
      //把对方增加
      to.balance += money
      to.deposit(money)
    }
  }
//  def test(to:BankAccount):Unit ={
//    to.balance = 0
//  }
}



object Test11041 {
  def main(args: Array[String]): Unit = {
    var xiaoming = new BankAccount(0)
    var xiaohua = new BankAccount(100)
    //存入200
    xiaohua.deposit(200)
    //取出150
    xiaohua.withdraw(150)

    //转账给小明
    xiaohua.transfer(xiaoming,100)

    xiaohua.showMoney()
    xiaoming.showMoney()

//    println(xiaohua.balance)


  }
}

输出结果

现在的余额是:200
现在的余额是:0