C++, the definitive curly brace language. Or is it?

A basic class

In C++, classes have member functions, member variables, class functions and class variables. Accessibility can be one of public, protected or private, with public and private being the most common.

class Animal {
  // Default access modifier at beginning of class is private
  public: // Everybody can access this

  // Constructors
  Animal(); 
  Animal(bool alive = true);
  Animal(const Animal&); // Copy constructor

  // Destructor
  ~Animal();

  // Virtual function, can be overruled by a derived class
  virtual string getDNA();

  // A pure virtual function must be defined in a derived class. 
  // This class makes it an abstract class
  virtual int getPopulation() = 0;

  protected:
  private:
};

A derived class

A derived class inherits from a base class. Functions from the base class can be explicitly called by using the class name as a specifier.

class Rabbit : Animal {

  public: 

  // Member variables
  int numberOfChildren;

  // Member functions
  Rabbit createOffspring();
  // Constructor
  Rabbit(string name) : Animal() { 
    numberOfRabbits++; // Not thread-safe but ok for this example
  }
  Rabbit(const Rabbit &originalRabbit); // Copy constructor
  Rabbit~() {numberOfRabbits--; } // Destructor

  virtual string description() = 0;
  protected: // Accessible by derived classes

  private: // Only accessible from class and friends
  virtual string getName(); // Can be redefined in a derived class
  string name;

  virtual string getDNA() = 0;

  static int numberOfRabbits; // Class variable

  public:
  virtual int getPopulation() {return Rabbit.getRabbitPopulation(); }
  static int getRabbitPopulation() const { return numberOfRabbits; } // Class function

  friend void print(Rabbit &); 
};

// Definition of a class outside the class declaration
Rabbit::jump() {
}

Some other definitions

Implementation of the class functions and class variables can be defined outside of the class.

// Friend functions, not member of class
void print(Rabbit &rabbit) {
  std::cout << rabbit.name;
}
int Rabbit::numberOfRabbits = 0; // Initialization outside of class

Comment

Anatomy of a C++ class

A basic class

A derived class

Some other definitions