How to overload << operator in derived classes on c++ [duplicate] - c++11

Question

This question already has answers here:
Making operator<< virtual?
(3 answers)
Closed 2 months ago.
In my example, I have two classes: Parent and Child. I'm using a vector of pointers to Parent (vector<Parent*> v;) and I'm inserting objects of both classes into v. I'm trying to print the classes attributes overloading the operator <<. My code prints the Parents attributes (name and age) and I would like to know how to print the derived attributes from Parent and the Child's own attribute.
class Parent{
friend ostream &operator<<(ostream &saida, Parent &parent){
out << "Name: " << parent.name << ", Age: " << parent.age << "." << endl;
return out;
}
public:
Parent(string name, int age){
this->name = name;
this->age = age;
}
string& getName(){
return name;
}
int& getAge(){
return age;
}
private:
string name;
int age;
};
class Child: public Parent{
friend ostream &operator<<(ostream &out, Child &child){
out << "Name: " << child.name << ", Age: " << child.age << ", School: " << child.school << "." << endl;
return out;
} // <- Don´t know what to do here
public:
Child(string name, int age, string school): Parent(name, age){
this->school = school;
}
string& getType(){
return type;
}
private:
string school;
};
int main(){
vector<Father*> v;
v.push_back(new Parent("Father", 30));
v.push_back(new Child("Child", 10, "School"));
for(int i = 0; i < v.size(); i++){
cout << *v[i];
}
return 0;
}
It prints:
Name: Father, Age: 30
Name: Child, Age: 10

Answer 1

In Parent:
friend std::ostream &operator<<(std::ostream& out, Parent const& parent){
parent.print(out);
out << ".\n";
return out;
}
virtual void print(std::ostream& out) const {
out << "Name: " << name << ", Age: " << age;
}
in Child:
void print(std::ostream& out) const override {
Parent::print(out);
out << ", School: " << school;
}
and things should work the way you want.
To use C++'s object inheritance system and get dynamic dispatch, you need to use virtual dispatch. Here, I forward the operator<< to a virtual print method.
This print method doesn't include the ".\n" on purpose; that allows children to add new fields easily.
The Child class does not have a operator<<, but uses the Parent's operator<<.