第四章例题4_3和4_4

例4_3
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 computeArea(){
  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.computeArea();
area2=laderTwo.computeArea();
System.out.println("laderOne的above,bottom,height:"+
laderOne.above+","+laderOne.bottom+","+laderOne.height);
    System.out.println("laderOne的面积："+area1);
System.out.println("laderTwo的above,bottom,height:"+laderTwo.above+
","+laderTwo.bottom+","+laderTwo.height);
System.out.println("laderTwo的面积："+area2);
}
} 
结果：
---------- 运行 ----------
laderOne的above,bottom,height:16.0,26.0,100.0
laderOne的面积：2100.0
laderTwo的above,bottom,height:300.0,500.0,20.0
laderTwo的面积：8000.0

输出完成 (耗时 0 秒) - 正常终止

例4_4:

class Lader
{
double above,height;
static double bottom;
public void setAbove(double a){
  above=a;
}
    public void setBottom(double b){
  bottom=b;
}
double getAbove(){
  return above;
}
        double getBottom(){
        return bottom;
        }
}
class Example4_4{
      public static void main(String args[]){
      Lader.bottom=60;
      Lader laderOne,laderTwo;
      System.out.println("现在所有Lader对象的bottom都是"+Lader.bottom);
      laderOne=new Lader();
      laderTwo=new Lader();
      System.out.println("laderOne的bottom:"+laderOne.getBottom());
      System.out.println("laderOne的bottom:"+laderOne.getBottom());
      laderOne.setAbove(11);
      laderTwo.setAbove(22);
      laderTwo.setBottom(100);
      System.out.println("现在所有的Lader对象的bottom都是："+Lader.bottom);
      System.out.println("laderOne的above:"+laderOne.getAbove());
 System.out.println("laderTwo的above:"+laderTwo.getAbove());
   }
}

 

结果：

---------- 运行 ----------
现在所有Lader对象的bottom都是60.0
laderOne的bottom:60.0
laderOne的bottom:60.0
现在所有的Lader对象的bottom都是：100.0
laderOne的above:11.0
laderTwo的above:22.0


输出完成 (耗时 0 秒) - 正常终止