Не получается использовать указатель на метод класса

#include <iostream>
#include <cmath>
 
using namespace std;
 
class Shape
{
    public:
    virtual void showShape()=0;
    virtual double getArea()=0;
    friend std::ostream& operator <<(std::ostream &out, const Shape &p)
    {
        return p.print(out);
    }
    virtual std::ostream& print(std::ostream &out) const =0;
    ~ Shape()
    {
    }
 
};
 
class Point
{
public:
    int m_x = 0;
    int m_y = 0;
 
 
    Point(int x, int y)
        : m_x(x), m_y(y)
    {
 
    }
 
    friend std::ostream& operator<<(std::ostream &out, const Point &p)
    {
        out << "Point(" << p.m_x << ", " << p.m_y  << ")";
        return out;
    }
    virtual std::ostream& print(std::ostream &out) const //override
    {
        out<<m_x<<m_y;
        return out;
    }
    
};
 
class Triangle: public Shape
{
private:
    Point m_1, m_2, m_3;
    
public:
    Triangle(Point f, Point s, Point t): m_1(f), m_2(s), m_3(t)
    {
    }
    virtual void showShape()
    {
        cout<<"  ."<<'\n'<<
              " ..."<<'\n'<<
              "....."<<endl;
    }
    virtual double getArea()
    {
        double det=1*(m_1.m_x*m_2.m_y-m_1.m_y*m_2.m_x)-1*(m_1.m_x*m_3.m_y-m_3.m_x*m_1.m_y)+1*(m_2.m_x*m_3.m_y-m_3.m_x*m_2.m_y);
        double S=.5*fabs(det);
        return S;
    }
    virtual std::ostream& print(std::ostream &out) const// override
    {
        out<<"Triangle(" <<m_1<<", " <<m_2<<", " <<m_3<<")";
        return out;
    }
    
};
 
class Circle: public Shape
{
private:
    Point m_cntr;
    int m_radius;
public:
    Circle(Point cntr, int radius): m_cntr(cntr), m_radius(radius)
    {
    }
    virtual void showShape()
    {
        cout<<"    ."<<'\n'<<
              " .      ."<<'\n'<<
              ".        ."<<'\n'<<
              " .      ."<<'\n'<<
              "     ."<<endl;
    }
    virtual double getArea()
    {
        return(3.14*double(pow(m_radius,1)));
    }
    
    virtual std::ostream& print(std::ostream &out) const// override
    {
        out<<"Circle("<<m_cntr<<", radius "<<m_radius<<")";
        return out;
    }
};
 
int main()
{
    Circle c(Point(1, 2), 7);
    std::cout << c << '\n';
    cout<<c.getArea()<<endl;
    Triangle t(Point(1, 2), Point(4, 8), Point(7, 8));
    std::cout << t << '\n';
    cout<<t.getArea()<<endl;
    t.showShape();
    c.showShape();
 
 
    int op=1;
 
   
    double (*pFcn)()=nullptr; /// Здесь!
    switch(op) ///
    {
        case 1: pFcn=&Shape::getArea; break; ///
    }
    c.pFcn();
 
    return 0;
}

    double (Shape::*pFcn)()=nullptr;
    switch(op) ///
    {
        case 1: pFcn=&Shape::getArea; break;
    }
    (c.*pFcn)();

#include <iostream>
 
using namespace std;
 
struct Base
{
    virtual ~Base(){};
    bool is_virtualCall;
    Base(bool b=true):is_virtualCall(b){}
    virtual void foo(){cout<<"\nfoo from base";}
};
 
struct Child :public Base
{
     ~Child(){};;
   Child(bool b=true):Base(b){}
   void foo()
   {
       if(is_virtualCall){
       cout<<"\nfoo from child";
       }
       else
            {
        Base::foo();
        }
       }
};
 
void cb_caller(Base &b, void(Base::*fun)(void))
{
    (b.*fun)();
}
 
int main()
{
Base base;
Child child_virt, child_novirt(false);
cb_caller(base, &Base::foo);
cb_caller(child_virt, &Base::foo);
cb_caller(child_novirt, &Base::foo);
 
    return 0;
}