代码呢

public class MyRectangle {
private int rxUp,ryUp,lxUp,lyUp;
int width;
int height;
int area1;

public MyRectangle(int rxUp,int ryUp,int lxUp,int lyUp){
this.lxUp=lxUp;
this.lyUp=lyUp;
this.rxUp=rxUp;
this.ryUp=ryUp;
}//构造方法

public int getW(){
width=lyUp-ryUp;
return width;
}

public int getH(){
height=rxUp-lxUp;
return height;
}

public int area(int width,int height){
this.getH();
this.getW();
area1=height*width;
return area1;
}

public String toString(){
return "宽："+width+" 长："+height+" 面积："+area1;
}

/*public int getrxUp(){
return rxUp;
}
public int getlxUp(){
return lxUp;
}
public int getryUp(){
return ryUp;
}
public int getlyUp(){
return lyUp;
}*/

public static void main(String args[]){
MyRectangle a= new MyRectangle(20,5,10,20);
a.area(a.getH(),a.getW());
System.out.println(a.toString());
}
}

public class MyCube extends MyRectangle{
MyRectangle mian;
int d;
long areac;
long vol;

public MyCube(int rxUp,int ryUp,int lxUp,int lyUp,int f){
super(rxUp,ryUp,lxUp,lyUp);
this.d=f;
}

public long volume(){
vol=mian.width*mian.height*d;
return vol;
}

public long cubearea(){
areac=2*(super.area(mian.width,mian.height)+super.area(mian.width,d)+super.area(d,mian.height));
return areac;
}

public static void main(String args[]){
try{
MyCube mc=new MyCube(20,5,10,20,6);
//mc.getH();
//mc.getW();
System.out.println("立方体的表面积："+mc.cubearea());
System.out.println("立方体的体积："+mc.volume());
}catch(NullPointerException ex){
//System.out.println("the error is"+ex);
//ex.printStackTrace();
System.out.println("the error is:"+ex.getMessage());
}
}
}

我帖了代码了啊
怎么还是没动静呢？？？
帮帮我啊
很向知道为什么啊

一个JAVA里不能有2个PUBLIC类

class MyRectangle {
private int rxUp,ryUp,lxUp,lyUp;
int width;
int height;
int area1;

public MyRectangle(int rxUp,int ryUp,int lxUp,int lyUp){
this.lxUp=lxUp;
this.lyUp=lyUp;
this.rxUp=rxUp;
this.ryUp=ryUp;
}//构造方法

public int getW(){
width=lyUp-ryUp;
return width;
}

public int getH(){
height=rxUp-lxUp;
return height;
}

public int area(int width,int height){
this.getH();
this.getW();
area1=height*width;
return area1;
}

public String toString(){
return "宽："+width+" 长："+height+" 面积："+area(width,height);
}

/*public int getrxUp(){
return rxUp;
}
public int getlxUp(){
return lxUp;
}
public int getryUp(){
return ryUp;
}
public int getlyUp(){
return lyUp;
}*/
}

class MyCube extends MyRectangle{

int d;
long areac;
long vol;

public MyCube(int rxUp,int ryUp,int lxUp,int lyUp,int f){
super(rxUp,ryUp,lxUp,lyUp);
this.d=f;
}

public long volume(){
vol=super.width*super.height*d;
return vol;
}

public long cubearea(){
areac=2*(super.area(super.width,super.height)+super.area(super.width,d)+super.area(d,super.height));
return areac;
}
}
public class bc_china{
public static void main(String args[]){
try{
MyCube mc=new MyCube(20,5,10,20,6);
//mc.getH();
//mc.getW();
System.out.println("立方体的表面积："+mc.cubearea());
System.out.println("立方体的体积："+mc.volume());
}catch(NullPointerException ex){
//System.out.println("the error is"+ex);
//ex.printStackTrace();
System.out.println("the error is:"+ex.getMessage());
}
}
}

--------------------Configuration: <Default>--------------------
立方体的表面积：300
立方体的体积：900

Process completed.

[此贴子已经被作者于2007-11-2 22:40:40编辑过]

这个我知道
只是在这里我把他们放在一起
在我的电脑上运行的时候
是存在了两个文件
不过
还是谢谢啦