castdemo1.java

来自「java课件 java课件 java课件 java课件」· Java 代码 · 共 20 行

//CastDemo1.java
public class CastDemo1{
  static void display(GeometricShape obj){
    if(obj instanceof Circle){
      System.out.println("This is a circle.");
      System.out.printf("The area = %6.2f%n",obj.area());
        
    }else if(obj instanceof Cylinder){
      System.out.println("This is a cylinder.");
      System.out.printf("The volume = %6.2f%n",((Cylinder)obj).volume());
    }
}
  public static void main(String args[]){
    GeometricShape obj1=new Circle(5);
    GeometricShape obj2=new Cylinder(5,10);
    display(obj1);
    display(obj2);     
  }
}