simple this example

#include <iostream>
#include <memory>

using namespace std;

class ASimpleClass{
    void do_a();
public:
    void do_stuff();
};

void ASimpleClass::do_stuff(){
    this->do_a();
    do_a();
}

void ASimpleClass::do_a(){
    cout << "ASimpleClass::do_a() executed" << endl;
}


class ABaseClass {
protected:
    virtual void do_a() = 0;
public:
    virtual void do_stuff();
    virtual ~ABaseClass();
};

void ABaseClass::do_stuff(){
    cout << "ABaseClass::do_stuff() executed" <<endl;
}

ABaseClass::~ABaseClass(){}

class ADerivedClass : public ABaseClass{
protected:
    void do_a() override;
public:
    void do_stuff() override;
};

void ADerivedClass::do_stuff(){
    do_a();
    this->do_a();
}

void ADerivedClass::do_a(){
    cout << "ADerivedClass::do_a() called" << endl;
}

int main()
{
    unique_ptr<ASimpleClass> a = unique_ptr<ASimpleClass>( new ASimpleClass());
    a->do_stuff();

    unique_ptr<ABaseClass> b = unique_ptr<ABaseClass>( new ADerivedClass());
    b->do_stuff();
    return 0;
}