设计一个名为 Rectangle的类表示矩形

#include<bits/stdc++.h>
#include<math.h>
using namespace std;
class Rectangle
{
private:
    float length;
    float width;
public:
    void Set(float l,float w)
    {
        length=l;
        width=w;
    }
    void getArea()
    {
        float s;
        s=length*width;
        cout<<"该长方形的面积为："<<s<<endl;
    }
};
int main()
{
    Rectangle r1;
    float l,w;
    cin>>l>>w;
    r1.Set(l,w);
    r1.getArea();

}

class Rectangle
{
private:
    float length;
    float width;
public:
    Rectangle() {}
    Rectangle(float l,float w) {length = l;width = w;}
    float getArea() {return length * width;}
};

int main()
{
    Rectangle r(10.0,20.0);
    float area = r.getArea();
    cout<<"矩形面积为:"<<area<<endl;
    return 0;
}