Single Inheritance

Single inheritance enables a derived class to inherit properties and behavior  from a single parent class. 

Example:        

Syntax
         class A
                {
                        -------
                        -------
                };
                class B : visibility_label A
                {
                        -------
                        -------
                };

Sample program
  
    class Shape
    {
        protected:
                float width, height;
        public:
                void set_data (float a, float b)
                {
                        width = a;
                        height = b;
                }
    };

    class Rectangle: public Shape
    {
        public:
                float area ()
                {
                        return (width * height);
                }
    };

    class Triangle: public Shape
    {
        public:
                float area ()
                {
                        return (width * height / 2);
                }
    };

    int main ()
    {
                Rectangle rect;
                Triangle tri;
                rect.set_data (5,3);
                tri.set_data (2,5);
                cout << rect.area() << endl;
                cout << tri.area() << endl;
                return 0;
    }

Output:
    15
     5

Advantages:

• It allows a derived class to inherit the properties and behaviour of a base class, thus enabling code re-usability as well as adding new features to the existing code. This makes the code much more elegant and less repetitive.
• Single inheritance is safer than multiple inheritance if it is approached in the right way. It also enables a derived class to call the parent class implementation for a specific method if this method is overridden in the derived class or the parent class constructor. 

Disadvantage:

• In Inheritance, base class and child classes are tightly coupled. Hence If you change the code of parent class, it will affect all the child classes of it.