virtual.h

#ifndef __cpp01__virtual__
#define __cpp01__virtual__

#include <iostream>


class Base {
public:
    virtual int print(const char *) = 0;
    ~Base();
};


class ChildA : public Base {
public:
    int print(const char *);
};

class ChildB : public Base {
public:
    int print(const char *);
};

void print(Base *, const char *);
void virtual_go();

#endif /* defined(__cpp01__virtual__) */