静态数据成员

#include <iostream>

using namespace std;

class Box
{
public:
    Box(int,int);
    int volume();
    static int height;
    int width;
    int length;

private:

};

Box::Box(int w,int len)
{
    width=w;
    length=len;
}
int Box::volume()
{
    return (height*width*length);
}
int Box::height=10;
int main()
{
    Box a(15,20),b(20,30);
    cout<<a.height<<" "<<b.height<<" "<<Box::height<<endl;
    cout<<a.volume()<<endl;
}