定义一个矩形类，包含有长length、宽width两种属性，构造方法(要求写出初始化长和宽)和计算面积方法findAr

举一返3吧~
public class area {

private double length;
private double width;
private double area;
public double findArea(double length,double width){
area=length*width;
return area;

}

public static void main(String[] args) {
// TODO Auto-generated method stub
area ee=new area();
ee.findArea(10,10);
System.out.println("面积="+ee.findArea(10,10));

}

}

class Rectangle {
double length;
double width;
public:
Rectangle( double len = 10, double wid = 10 ) { length = len; width = wid; }
double findArea() { return length * width; }
};