java问题 用类来描述一个矩形。矩形有宽和高两个成员变量，和求周长，求面积两个成员方法。在mai

// 矩形
public class RectangleDemo {

public static void main(String[] args) {
RectangleDemo demo = new RectangleDemo(12, 32);

System.out.println(demo.getPerimeter());
System.out.println(demo.getArea());

demo = new RectangleDemo();

System.out.println(demo.getArea());
System.out.println(demo.getPerimeter());

demo.setHeight(50);
demo.setWidth(30);

System.out.println(demo.getArea());
System.out.println(demo.getPerimeter());
}

// 求周
public double getPerimeter() {
return (height + width) * 2;
}

// 求面积
public double getArea() {
return height * width;
}

public RectangleDemo(double height, double width) {
this.height = height;
this.width = width;
}

public RectangleDemo() {
this.height = 10;
this.width = 10;
}

private double height;// 高度
private double width;// 宽度

public double getHeight() {
return height;
}

public void setHeight(double height) {
this.height = height;
}

public double getWidth() {
return width;
}

public void setWidth(double width) {
this.width = width;
}

}
编写矩形类RectangleJava程序矩形类两数据员别rLength宽rWidth通getLength()、getWidth()、getArea()别查看矩形、宽面积通setLength()setWidth()重新设置矩形宽