Static data members and static member function, C/C++ Programming

Assignment Help:

Static Data Members:

A data member inside the class can construct as static data member.   There are few

guidelines to be followed when declaring static data member.

  • It is declared as a private data member.
  • Only one copy of the static data member is created any numbers of objects are created from that class. Therefore the static data member will be same for all the objects created.
  • The static member must be defined outside the class like function with class name.
  • The static member can be initialized in the definition and can be used only within its class.

 

The following program will give clear difference between static data count and regular data number members.  The static data is common to all objects but regular data is unique to its object.

 

class item

{int number; static int count; public:

void getdata()

{++count;

number=count;

}

void putdata(void)

{cout<<"Count is "<

cout<<"Number is "<

}

};

int item::count=0;

int main()

 

 

{           clrscr();

item x,y,z; //Three object produced from class item x.getdata();

y.getdata();

z.getdata();

x.putdata(); The count is 3 and number is 1

y.putdata(); The count is 3 and number is 2 z.putdata(); The count is 3 and number is 3

return 0;

}

 

Static Member Function:

The static member function can be specified like static data member.  It works asc a static member data except the static member data is used in static member function.

Rules of Static Member function are given below:

  • The static member function can read static data member only from its class.
  • The static member function is called using class name not object name. class_name::static_function_name( ); It can also be called using object.static_fun( ).

 

The given program will illustrate how the static member function is worked.

 class find

{static int count;

int code;

public:

static void showcount(void)

{cout<<"Count is " <

}

void setcode(void)

{code = ++count;

}

void setcount(void)

{ cout<<"Code is " <

}

};

int find ::count=0;

int main()

{clrscr();

find x,y,z;

x.setcode(); // Code and count is 1. y.setcode(); //Code and count is 2 find::showcount(); //Count is 2

 

z.setcode(); //Code and count is 3 find::showcount(); //Count is 3

 

x.setcount(); // Code is 1 for object x.

 

 

 

 

y.setcount(); // Code is 2 for object y. z.setcount(); // Code is 3 for object z.

 

x.setcode(); // Code and count is 4. y.setcode(); //Code and count is 5 z.setcode(); //Code and count is 6 find::showcount(); //Count is 6

//The value of code will increase from its previous value of that object.

x.setcount(); // Code is 4 for object x. y.setcount(); / Code is 5 for object x. z.setcount(); // Code is 6 for object x.

return 0;

}

 

Since the count is declared as static it has only one copy irrespective of number of objects created.   When static count function called again and again it will increase count for all the objects created simultaneously therefore the count will be uniform for all object, but for the data member code it is unique for each object created because it is not a static data member.  Therfore from the above example there will only one value for count data member irrespective of number of objects constructed since it is a static data member, where as for code data member the value will be different for each object.


Related Discussions:- Static data members and static member function

Displays the temperature conversion chart on the screen, Write a program th...

Write a program that displays the following temperature conversion chart on the screen as follows below. Hint: c = 5.0/9.0 * (f - 2) C = degrees in Celsius F = degree in F

Project, Project Overview A certain financial institution (bank) wishes to ...

Project Overview A certain financial institution (bank) wishes to promote its new business products/services by conducting road shows in rural areas. Their aim is to encourage peop

Explain the preprocessor directives, The Preprocessor Directives A prep...

The Preprocessor Directives A preprocessor directive which starts with a hash '#' ,is an instruction to the preprocessor, which acts on the source code before the compilation p

Constructors and destructors, Constructors and Destructors: A Class is ...

Constructors and Destructors: A Class is defined as constructor by declaring a constructor in the form of function inside the class.  In other word a function in the name of

Can any constructor throw an exception?, Can any constructor throw an excep...

Can any constructor throw an exception? How to handle error while the constructor fails?

String, palindrome is a string that reads the same from both the ends. Give...

palindrome is a string that reads the same from both the ends. Given a string S convert it to a palindrome by doing character replacement. Your task is to convert S to palindromes

Inheritance, example of program to ad two numbers

example of program to ad two numbers

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd