Class-based OOP without "class"

cplusplus.cpp

// base class
class Animal {
  private:
    // private property
    int age;
    bool sex;

  public:
    // constructor
    Animal (int age, bool sex) {
      this->age = age;
      this->sex = sex;
    }
  
    // public method
    virtual string greet() {
      return '';
    }
  
    int getAge () {
      return age;
    }
  
    string getSex () {
      return sex ? "male" : "female";
    }
};

// subclass: Dog
class Dog: public Animal {
  public:
    // overriding method
    string greet() {
      return "woof";
    }
  
    // own method
    string bark() {
      return this->greet();
    }
};

// subclass: Human
class Human: public Animal {
  private:
    // own private property
    string name;
  
  public:
    // own constructor
    Human (int age, bool sex, string name)
      // call super-constructor
      : Animal(age, sex)
    {
      this->name = name;  
    }
  
    // overriding method
    string greet() {
      return "Greetings! I'm " + this->name;
    }
  
    string getName() {
      return name;
    }
};