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

Print the sorted output on the console, Question 1 Describe the theory beh...

Question 1 Describe the theory behind class templates and function templates along with relevant programming examples Question 2 With the help of suitable programming example

Matrix transposition cipher, write a C rpogram that can display the transpo...

write a C rpogram that can display the transpose form of a ciphertext matrix.Prompt users to provide row and coloumn number of matrix.Then user will input plaintext and the program

Example of function - c program, Here is a short program. It prints out the...

Here is a short program. It prints out the value of a variable "x". Ernie and Bert disagree about what will be printed: Ernie says, the value gets changed in "changeX" so it will p

HASH., Define hash functions. Explain the Division method, Mid square metho...

Define hash functions. Explain the Division method, Mid square method and Folding method of hash functions.

String, what is a string?

what is a string?

Describe faster ++i or i++, A: The answer to this lies actually, how they u...

A: The answer to this lies actually, how they used. Along ++i(PreIncrement) the variable is incremented and new value is returned. Thus it needs one instruction to increment the va

Fill an array of randomly generated integers, The task consists of two part...

The task consists of two parts which are both preferably implemented in one source file. Towards the end of this document you will find a code skeleton that you must assume. Start

Car rental system, Car Rental System This system tracks cars in a rental co...

Car Rental System This system tracks cars in a rental company. Each car has a number (assume its plate number), type (small car, four wheel car), and status (rented, available). T

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