第一次编写，真的不懂自己怎样修改，希望大家可以看一下代码如下：1定义一个描述矩形的类Rectangle包括的数据成员有宽width和长length （2计算矩形周长（3计算矩形面积（4改变矩形大小

#include
using namespace std;
void main(void)
{
class Rectangle
{
public:
void perimer(int width,int length);
void area(int width,int length);
private:
int width,length;
};
inline void Rectangle::perimer(int width,int length)
{
cout<<"width:"<
cin>>width>>length;
perimer=width+length;
}
inline void Rectangle::area(int width,int length)
{
cout<<"width:"<
cin>>width>>length;
area=width*length;
}

void main(void)
{
    Rectangle g;
    g.perimer();
    g,area();
}

}

#include <iostream>
using namespace std;

class Rectangle
{
public:
    Rectangle(int w = 0, int l = 0) : width(w), length(l) {}
    void perimer();
    void area();
    void set(int w, int l)
    {
        width = w;
        length = l;
    }

private:
    int width, length;
};

void Rectangle::perimer()
{
    cout << "perimer: " << 2 * (width + length) << endl;
}
void Rectangle::area()
{
    cout << "area: " << width * length << endl;
}

int main(void)
{
    int w, l;
    Rectangle g(1, 2);
    g.perimer();
    g.area();

    cin >> w >> l;
    g.set(w, l);
    g.perimer();
    g.area();
}