🟣 OOP · Lesson 43

Static Data Members and Static Functions

What is Static Data Members and Static Functions?

Static Data Members and Static Functions
Static members belong to the class rather than individual objects. They are shared by all objects of the class.

Level
🟣 Object-Oriented Programming

Example File
static-members.cpp

Main Focus
Concept + syntax + practical C++ program

Why should you learn this?

It helps you write correct and readable C++ programs.
It is used repeatedly in school practicals, projects and competitive programming.
It builds the base for advanced topics such as OOP, STL and data structures.

Important Terms

Term	Meaning / Use
static member	Static Data Members and Static Functions programming में Static member use होता है।
class variable	Static Data Members and Static Functions programming में Class variable use होता है।
shared value	Static Data Members and Static Functions programming में Shared value use होता है।
static function	Static Data Members and Static Functions programming में Static function use होता है।

Syntax / Pattern

C++

static data_type member;

Example Program

main.cpp

#include <iostream>
using namespace std;
class Student{
public:
    static int count;
    Student(){ count++; }
};
int Student::count = 0;
int main(){ Student a,b,c; cout << Student::count; }

Expected Output

Program Explanation

count is shared by all objects.
Constructor increases count whenever an object is created.

Exam Tip: In C++ practical answers, write the logic first, then the program, then expected output. For theory, always include one suitable example.

Where will you use it?

object counting
shared configuration
factory methods

Common Mistakes

Forgetting to define static data member outside class.
Accessing non-static data from static function directly.

Practice Tasks

Count number of objects created.
Create static schoolName member.

Summary

Static Data Members and Static Functions एक ज़रूरी C++ topic है। परिभाषा सीखें, syntax समझें, example program चलाएं और फिर practice tasks हल करके concept मज़बूत करें।