Inheriting from Multiple Base Classes

In the past articles we saw how we can make a class inherit from another class.
This way we could have a new class with features of the base class without explicitly
defining them. But what if, we want to have a new class with features form more
than one class. In other words, Is it possible for a derived class to inherit
multiple base classes (two or more).

Yes it’s possible!

The general from for deriving a class from multiple classes is:


  class derived-class:access-specifier base1,access-specifier base2...
  {
    ...
    ...
    ...
  };

The following example program illustrates multiple inheritance practically:


  // -- INHERITANCE --
  // Program to illustrate multiple
  // inheritance
  #include<iostream.h>

  // base class (1)
  class base1
  {
  protected:
    int a;

  public:
    void showa(){cout<<a<<"\n";}
  };

  // base class (2)
  class base2
  {
  protected:
    int b;

  public:
    void showb(){cout<<b<<"\n";}
  };

  // derived class
  // inherits both base1 and base2
  // NOTE: Both the base class have
  // access-specifier
  class derived:public base1,public base2
  {
  protected:
    int c;

  public:
    void set(int n1,int n2,int n3)
    {
      a=n1;b=n2;c=n3;
    }

    void show()
    {
      cout<<a<<"\n"<<b<<"\n"<<c<<"\n";
    }
  };

  void main(void)
  {
    derived d;

    d.set(10,20,30);

    // access base's members
    d.showa();
    d.showb();


    // access derived's member
    d.show();
  }