Problem G: 平面上的点和线——Point类、Line类 (VII)

#include <iostream>
using namespace std;
class Point
{
 
friend class Line;
private:
    double st,ed;
    static int now,sum;
public:
    Point():st(0),ed(0){sum++;now++;}
    Point(double stt ,double edd ):st(stt),ed(edd){sum++;now++;}
    Point (const Point &p)
    {st = p.st;ed= p.ed;  sum++;now++;}
    double x() const {return st;}
    double y() const {return ed;}
    ~Point (){now--;}
   static void showCounter(){cout<<"Current : "<<now<<" points."<<endl;}
   static void showSum(){cout<<"In total : "<<sum<<" points."<<endl;}
};
int Point::sum=0;
int Point::now=0;
 
class Line
{
    friend class Point;
 
    private :
    Point st_,ed_;
    public:
        static int s;
        static int n;
    Line():st_(0,0),ed_(0,0)
    {s++;n++;}
    Line(Point &sst, Point &eed):st_(sst),ed_(eed)
    {s++;n++;}
    Line(double x1,double y1,double x2,double y2):st_(x1,y1),ed_(x2,y2)
    {s++;n++;}
    ~Line()
    { n--;}
    Line(const Line &l):st_(l.st_),ed_(l.ed_)
    {s++;n++;}
 
 
    Line setLine(double x1,double y1,double x2,double y2)
{
    st_.st=x1;
    st_.ed=y1;
    ed_.st=x2;
    ed_.ed=y2;
    return *this;}
    Line &setLine(const Point &p  ,const Point &q)
{
    st_=p;
    ed_=q;
    return *this;
}
    Line &setLine(const Line &p)
{
    st_=p.st_;
    ed_=p.ed_;
    return *this;
}
 
void readLine()
{
  double x1,y1,x2,y2;
  char in;
  cin>>x1>>in>>y1>>x2>>in>>y2;
    st_.st=x1;
    st_.ed=y1;
    ed_.st=x2;
    ed_.ed=y2;
}
 
/*const Point &start()const
    {return st_;}
const Point &end()const
    {return ed_;}
 
void setStart(Point &s)
    {st_=s;}
void setEnd(Point &e)
    {ed_=e;}*/
 
static void showCounter(){cout<<"Current : "<<n<<" lines."<<endl;}
static void showSum(){cout<<"In total : "<<s<<" lines."<<endl;}
 
};
 
 
int Line::s=0;
int Line::n=0;
 
 
int main()
{
    int num, i;
    Point p(1, -2), q(2, -1), t;
    t.showCounter();
    t.showSum();
    std::cin>>num;
    Line line[num + 1];
    for(i = 1; i <= num; i++)
    {
        Line *l1, l2;
        l1->showCounter();
        l1->showSum();
        l1 = new Line(p, q);
        line[i].readLine();
        p.showCounter();
        p.showSum();
        delete l1;
        l2.showCounter();
        l2.showSum();
        q.showCounter();
        q.showSum();
    }
    Line l1(p, q), l2(p,t), l3(q,t), l4(l1);
    Line::showCounter();
    Line::showSum();
    Point::showCounter();
    Point::showSum();
    Line *l = new Line[num];
    l4.showCounter();
    l4.showSum();
    delete[] l;
    t.showCounter();
    t.showSum();
}