Page 101 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes You should get the following output from this program.
The present value of count is 1
The present value of count is 2
The present value of count is 3

The present value of count is 4
The present value of count is 5

Did u know? What is the use of static members?
A typical use of static members is for recording data common to all objects of a class. For
example, you can use a static data member as a counter to store the number of objects of a
particular class type that are created.

5.1.1 Static Member Functions

Just as data members can be static, member functions can also be static. A static function is a
member function of a class and it manipulates only static data member of the class. It acts as
global for members of its class without affecting the rest of the program. Static members serve
the purpose of reducing the need for global variables by providing alternatives that are local to
a class.

A static member function is not a part of objects of class. It is instance dependent and can be
accessed directly by using the class name and scope resolution operator. If it is declared and
defined in a class, the keyword static should be used only in declaration part.

The following program demonstrates the use of static member function which accesses static
data. The data member count and the function disp( ) are declared static in the class counter. But
the variable count is initialized to 0 outside the class.
#lnclude <iostream.h>
#lnclude <conin.h>
class counter
{

private:
static int count;
public:
counter()
{
++count;
}

static void disp();
};
int counter::count=0;
void counter::disp()

94 LOVELY PROFESSIONAL UNIVERSITY