Полиморфный конструктор [C++]

class A {
public:
int c,b;
virtual A(int c,int b){
this-> c=c;
this-> b=b; 
}
};

#include <iostream>
#include <math.h>
using namespace std;
class Point {
public:
int x,y,x1,y1;
virtual void show() {
cout<< "x="<<x<<endl;
cout<< "y="<<y<<endl;
cout<< "x2="<<x1<<endl;
cout<< "y2="<<y1<<endl;}
}; Point A;
class Line : public Point {
 public:
 int qx,qy;
 int dx,dy;
 int l;
 float line;
 virtual float Lline(int x, int y, int x1, int y1){
    dx=x1-x;
    dy=y1-y;
    qx=pow(dx, 2);
    qy=pow(dy, 2);
    l= qx+qy;
    line = sqrt(l);
    return line;}
    void show(float ll){
    cout << "L=" << ll<<endl;}
}; Line B;
class Circle : public Line{
public:
virtual float circle (float line){
float ccircle;
ccircle = line*line*3.14;
return ccircle;
}
void show(float cc){
cout << "S=" << cc<< endl;}
}; Circle C;
class Sphere : public Circle{
public:
virtual float sfera(float circle,float line){
float sfrere;
sfrere = circle*line*0.75;
return sfrere;
}
void show(float sh) {
cout << "V="<< sh<<endl;}
}; Sphere D;
int main () {
int x,y,x1,y1;
float line,circle,sphere;
cout << "Point(1):"<< endl;
cout << "Input X= ";
cin >> A.x;
cout << "Input Y= ";
cin >> A.y;
cout << "Point(2):"<<endl;
cout << "Input X2= ";
cin >> A.x1;
cout << "Input Y2= ";
cin >> A.y1;
line = B.Lline(A.x,A.y,A.y1,A.y1);
circle = C.circle(line);
sphere = D.sfera(circle,line);
A.show();
B.show(line);
C.show(circle);
D.show(sphere);
}
}

#include <iostream>
 
struct Point
{
   int x, y;
};
 
struct Line
{
   Point x, y;
};
 
struct Circle
{
   Point center;
   Line radius;
};

class Point
{
private:
    int x,y;
public:
    Point();
    Point(int,int);
};
 
Point::Point()
{
    x=0;
    y=0;
}
 
Point::Point(int x,int y)
{
    this->x=x;
    this->y=y;
}