FRIEND FUNCTION
A non member function may not possess an access to the private data of a class . But , there could possibly be a scenario in which we want two classes to share a specific function . To illustrate , take into account a case where two classes , supervisor and Warden , are defined . We want to use a function Salary( ) to work on the object of both these classes . In this kind of situations , C++ enables the common function to be created friendly with the two the classes , thus enabling the function to have accessibility to the private data of these classes . This kind of a function will not need to be member of any of these classes .
Syntax:
class ABC
{
.....
.....
public:
.....
.....
friend void xyz(void);
};
STATIC MEMBER FUNCTION
Similar to static member variable , you can have static member function . When we declare a member of a class as static it implies regardless of how many objects of the class are built ,there is certainly just one copy of the static member .
A static member is shared by all objects of the class . Almost all static data is initialized to zero whenever the first object is created , in the event that no other initialization exists. We can't place it in the class definition however it can be initialized outside the class. A member function which is declared static possesses the following characteristics :
#include <iostream>
using namespace std;
class Cuboid
{
public:
static int objectCount;
// Constructor definition
Cuboid(float a=2.0, float b=2.0, float c=2.0)
{
cout <<"Constructor called." << endl;
length = a;
breadth = b;
height = c;
// Increase every time object is created
objectCount++;
}
float Volume()
{
return length * breadth * height;
}
private:
float length; // Length of a Cuboid
float breadth; // Breadth of a Cuboid
float height; // Height of a Cuboid
};
// Initialize static member of class Cuboid
int Cuboid::objectCount = 0;
int main(void)
{
Cuboid Cuboid1(3.3, 1.2, 1.5); // Declare Cuboid1
Cuboid Cuboid2(8.5, 6.0, 2.0); // Declare Cuboid2
// Print total number of objects.
cout << "Total objects: " << Cuboid::objectCount << endl;
return 0;
}
A non member function may not possess an access to the private data of a class . But , there could possibly be a scenario in which we want two classes to share a specific function . To illustrate , take into account a case where two classes , supervisor and Warden , are defined . We want to use a function Salary( ) to work on the object of both these classes . In this kind of situations , C++ enables the common function to be created friendly with the two the classes , thus enabling the function to have accessibility to the private data of these classes . This kind of a function will not need to be member of any of these classes .
Syntax:
class ABC
{
.....
.....
public:
.....
.....
friend void xyz(void);
};
STATIC MEMBER FUNCTION
Similar to static member variable , you can have static member function . When we declare a member of a class as static it implies regardless of how many objects of the class are built ,there is certainly just one copy of the static member .
A static member is shared by all objects of the class . Almost all static data is initialized to zero whenever the first object is created , in the event that no other initialization exists. We can't place it in the class definition however it can be initialized outside the class. A member function which is declared static possesses the following characteristics :
- A static function will surely have access to just static members declared in the class .
- Syntax- class-name : : function-name ;
#include <iostream>
using namespace std;
class Cuboid
{
public:
static int objectCount;
// Constructor definition
Cuboid(float a=2.0, float b=2.0, float c=2.0)
{
cout <<"Constructor called." << endl;
length = a;
breadth = b;
height = c;
// Increase every time object is created
objectCount++;
}
float Volume()
{
return length * breadth * height;
}
private:
float length; // Length of a Cuboid
float breadth; // Breadth of a Cuboid
float height; // Height of a Cuboid
};
// Initialize static member of class Cuboid
int Cuboid::objectCount = 0;
int main(void)
{
Cuboid Cuboid1(3.3, 1.2, 1.5); // Declare Cuboid1
Cuboid Cuboid2(8.5, 6.0, 2.0); // Declare Cuboid2
// Print total number of objects.
cout << "Total objects: " << Cuboid::objectCount << endl;
return 0;
}
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