//果农为桔子树浇水
 public override void VisitOrange(Orange myClassB)
 {
     myClassB.PlantOrange();
     Console.WriteLine("果农为桔子树浇水");
 }
 //果农为桔子树松土
 public override void VisitOrange(Orange orange)
 {
     orange.PlantOrange();
     Console.WriteLine("果农为桔子树松土");
 }
 public override void VisitOrange(Orange orange) //果农为桔子树松土
 {
     orange.PlantOrange();
     Console.WriteLine("果农为桔子树松土");
 }
 public override void VisitOrange(Orange myClassB) //果农为桔子树浇水
 {
     myClassB.PlantOrange();
     Console.WriteLine("果农为桔子树浇水");
 }
 Banana banana = new Banana();                       //创建香蕉类
 public void PlantAppleOrange()
 {
     Console.WriteLine("------北京果园------");
     apple.PlantApple();                             //种植苹果树
     orange.PlantOrange();                           //种植桔子树
 }