A Class can be derived from another derived class. It is not uncommon that a class is derived from another derived class shown in the figure "Multilevel inheritance".
It’s clear with the above diagram that in
multilevel inheritance there is a concept of relation between grandfather, father and child.
The class A serves as a base class for the derived class B, which in turn serves as a base class for the derived class C. The class B is known as intermediate base class because it provides a link for the inheritance between A and C. The chain ABC is known as inheritance path.
Declaration
In C++, a derived class with multilevel inheritance can be declared as follows:The level of inheritance can be extended to any number of level depending upon the program requirements.
class A //Base class
{ ---------
--------- //body of class A
---------
};
class B : public A //B derived from class A
{ ----------
--------- //body of class B
----------
};
class C : public B //C derived from class B
{ ----------
--------- //body of class C
----------
};
//This process can be extended to any number of levels.
Multilevel Inheritance Example Programs
The following simple program written in C++ explains multilevel inheritance.
#include
#include
class B1
{
protected:
float m, n;
public:
assign (float x, float y)
{
m = x;
n = y;
}
}; //end base class B1
class B2 : public B1
{
public:
sum()
{
cout
}
}; //end derived class B2
class D1 : public B2
{
public:
product()
{
cout
}
}; //end derived class D1
main()
{
D1 x;
clrscr();
x .assign (10, 2);
x .sum ();
x .product();
getch();
}
Sum of 10 and 2 = 12
Product of 10 and 2 = 20
Example Program 2:
The following program prepares clint profile using multilevel inheritance.
#include
#include
class clint
{
char name[50],gender[15];
int age;
public:
void getdata()
{
cout
fflush(stdin); // to clear input stream
cin>>name;
cout
cin>>age;
cout
cin>>gender;
}
void display()
{
cout
cout cout
}
};
class employee: public clint
{
char company[100];
float salary;
public:
void getdata()
{
person::getdata();
cout
fflush(stdin);
cin>>company;
cout
cin>>salary;
}
void display()
{
clint::display();
cout
"
cout
Rs."
}
};
class programmer: public employee
{
int number;
public:
void getdata()
{
employee::getdata();
cout
language known: ";
cin>>number;
}
void display()
{
employee::display();
cout
language known: "
}
};
main()
{
programmer p;
cout
p.getdata();
cout
p.display();
getch();
return 0;
}
Output:
Enter Clint Name: Zeshan AliEnter Age: 20
Enter Gender: Male
Name of Company: CodeHim
Salary: $1000
Number of programming language known: 6
Displaying data
Name: Zeshan AliAge: 20
Gender: Male
Name of Company: CodeHim
Salary: $1000
Number of programming language known: 6
