Generic output operator overloading with inheritance - c++

Question

Given an abstract base class Object and 2 derived classes, Person and Gathering. Where Gathering is a data structure which stores pointers to Person or other Gathering pointers inside of an array.
I would like to override the output operator so it prints any type of Object. But I do not know how to override the operator properly so when it receives type Object it knows how to deal with it.
Here is a simple code that exemplifies what I'm trying to achieve:
#import <iostream>
#import <cstring>
class Object {
public:
virtual ~Object(){};
};
class Person : public Object {
private:
char * m_name;
public:
Person(char * input) {
m_name = new char[strlen(input)];
strncpy(m_name, input, strlen(input));
}
char* getName() const{
return m_name;
}
friend std::ostream& operator<<(std::ostream& os, const Person* p) {
os << p->getName();
return os;
}
};
class Gathering : public Object {
private:
int m_size;
Object* m_buffer;
public:
Gathering() : m_size(10)
{}
friend std::ostream& operator<<(std::ostream& os, const Gathering* v) {
for (int i=0; i<v->getSize(); i++) {
//Trying to send Object to outputstream..
os << "[" << v->getBuffer()[i] << "]";
}
}
int getSize() const {
return m_size;
}
Object* getBuffer() const {
return m_buffer;
}
};
I am very aware of what the problem is, how do Ideal with this? Any references or pointers are very appreciated.

Answer 1

You can add a virtual member function in Object, call it in your operator overload and implement it correctly for children classes.
class Object {
public:
virtual ~Object(){}
virtual void print(std::ostream&){}
friend std::ostream& operator<<(std::ostream& os, const Object& obj) {
obj.print(os);
return os;
}
};
class Gathering : public Object {
private:
int m_size;
Object* m_buffer;
public:
Gathering() : m_size(10)
{}
virtual void print(std::ostream& os) {
for (int i=0; i<v->getSize(); i++) {
os << "[";
m_buffer[i].print(os);
os << "]";
}
}
int getSize() const {
return m_size;
}
Object* getBuffer() const {
return m_buffer;
}
};
Also not related, but put a virtual destructor in your children classes, use a vector instead of your Object pointer m_buffer or at least initialise it in your constructor, but i guess you have school restrictions or something :)