使用lader类创建两个对象

class Lader{
double above,bottom,height;
Lader(){}
Lader(double a,double b,double h){
 above=a;
 bottom=b;
 height=h;
 }
 public void setAbove(double a){
  above=a;
 }
  public void setBottom(double b){
   bottom=b;
   }
   public void setHeight(double h){
    height=h;
    }
    double computerArea(){
     return(above+bottom)*height/2.0;
     }
    }
    public class Example4_1{
     public static void main(String args[]){
      double area1=0,area2=0;
      Lader laderOne,laderTwo;
      laderOne=new Lader();
      laderTwo=new Lader(10,88,20);
      laderOne.setAbove(16);
      laderOne.setBottom(26);
      laderOne.setHeight(100);
      laderTwo.setAbove(300);
      laderTwo.setBottom(500);
      area1=laderOne.computerArea();
      area2=laderTwo.computerArea();
      System.out.println("laderOne above,bottomandheight:"+laderOne.above+","+laderOne.bottom+","+laderOne.height);
      System.out.println("laderOne area:"+area1);
       System.out.println("laderTwo above,bottomandheight:"+laderTwo.above+","+laderTwo.bottom+","+laderTwo.height);
       System.out.println("laderTwo area:"+area2);
       }
       }