请教一道C++题目。。。在线等。。。

#include
#include
using namespace std;
class line;
class point
{
private:
int x;
int y;
static int cointp;
public:
friend class line;
friend float distance1(point &a,point&b)
{
float z;
z=sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
return z;
}
point()
{x=0;
y=0;
cointp++;}
point(int a,int b)
{x=a;
y=b;
cointp++;}
static void showcointp()
{
cout< }
};
class line
{
private:
point x1;
point x2;
static float length;
public:
line(point &a,point &b)
{
length=distance1(a,b);
}
void getlength()
{
cout< }
};
int point::cointp=0;
float line::length=0;
int main()
{
point A(1,1);
point B(-1,-1);
cout <<"A,B distance : " < point::showcointp();
line I(point(1,2),point(3,4));
I.getlength() ;
point::showcointp();
}

#include
#include

using namespace std;

class point {
public:
point(int _x,int _y):x(_x),y(_y){}
friend int distance(point& p1,point& p2);
private:
int x;
int y;
};
int distance(point& p1,point& p2){
return sqrt((p1.x1 - p2.x1) * (p1.x1 - p2.x1) + (p1.x2 - p2.x2) * (p1.x2 - p2.x2)) ;
}

int main(){
point A(1,1);
point B(-1,-1);
cout <<"A,B distance : " <
}
什么计数功能你自己加吧,很简单,可以hi我

class point{
public:
point(float _x = 0, float _y = 0) : x(_x), y(_y)
{
++pointNo;
}
~point()
{
--pointNo;
}
static int countp(){return pointNo;}
private:
friend float distance(const Point &, const Point &);
float x;
float y;
static pointNo;
}; // End of point class

float distance(const point &p1, const point &p2)
{
float distance = 0;
float DeltaX = 0;
float DeltaY = 0;

DeltaX = p2.x - p1.x;
DeltaY = p2.y - p1.y;

DeltaX *= DeltaX;
DeltaY *= DeltaY;

distance = sqrt(DeltaX + DeltaY);

return distance;
}

class line{
public:
line(point& _p1, point& _p2):p1(_p1),p2(_p2)
{
}
~line(){}
float get_length(){ return distance(p1,p2);}
private:
point p1;
point p2;
}

到511来 我告诉你