Static Function Members

Static Function Members:

By declaring a function member as static, you make it independent of any particular object of the class. A static member function can be called even if no objects of the class exist and the static functions are accessed using only the class name and the scope resolutionoperator ::.

A static member function can only access static data member, other static member functions and any other functions from outside the class.

Static member functions have a class scope and they do not have access to the this pointer of the class. You could use a static member function to determine whether some objects of the class have been created or not.

Let us try the following example to understand the concept of static function members:

#include<iostream>

usingnamespacestd;

classBox

{

public: staticintobjectCount;

// Constructor definition

Box(double l=2.0,double b=2.0,double h=2.0)

{

cout<<"Constructor called."<<endl; length= l;

breadth= b;

height= h;

//  Increase every time object is created

objectCount++;

}

doubleVolume()

{

return length * breadth * height;

}

staticintgetCount()

{

returnobjectCount;

}

private:

double length;// Length of a box

double breadth;// Breadth of a box

double height;// Height of a box };

//  Initialize static member of class Box

intBox::objectCount=0;

int main(void)

{

Print total number of objects before creating object.

cout<<"Inital Stage Count: "<<Box::getCount()<<endl;

BoxBox1(3.3,1.2,1.5);// Declare box1

BoxBox2(8.5,6.0,2.0);// Declare box2

// Print total number of objects after creating object.

cout<<"Final Stage Count: "<<Box::getCount()<<endl;

return0;

}

When the above code is compiled and executed, it produces the following result: InitalStageCount:0

Constructor called.

Constructor called.

FinalStageCount:2