Q8. Demonstrate the Use of Static Data Member and Static Member Function

Question:
Write a program to demonstrate the use of static data member and static member function.

My Approach

• Static Data Member:

  • Ye ek class-level variable hota hai.
  • Har object ka alag copy banne ke bajaye, ye sab objects ke liye common hota hai.

• Static Member Function:

  • Ye sirf static members ko access kar sakta hai.
  • Class ke objects create kiye bina bhi call kiya ja sakta hai.

Program Code

File Name: static_member_demo.cpp

#include <iostream>
using namespace std;
 
class Student {
private:
    string name;
    int rollNo;
 
    // Static data member
    static int studentCount;
 
public:
    // Constructor
    Student(string n, int r) : name(n), rollNo(r) {
        studentCount++; // har object ke banne par count increment
    }
 
    // Member function
    void display() {
        cout << "Name: " << name << ", Roll No: " << rollNo << endl;
    }
 
    // Static member function
    static void showCount() {
        cout << "Total Students: " << studentCount << endl;
    }
};
 
// Static data member ko class ke bahar initialize karna padta hai
int Student::studentCount = 0;
 
// ================= Main Function =================
int main() {
    Student s1("Intesab Ansari", 101);
    Student s2("Sumaira Khan", 102);
    Student s3("Rahul Sharma", 103);
 
    cout << "=== Student Records ===" << endl;
    s1.display();
    s2.display();
    s3.display();
 
    cout << "\n=== Using Static Function ===" << endl;
    Student::showCount();  // static function ko bina object ke call kiya
 
    return 0;
}

Sample Output

=== Student Records ===
Name: Intesab Ansari, Roll No: 101
Name: Sumaira Khan, Roll No: 102
Name: Rahul Sharma, Roll No: 103

=== Using Static Function ===
Total Students: 3

Explanation

1. studentCount ek static data member hai jo total students track kar raha hai.
2. Har naya Student object banne par constructor usse increment kar deta hai.
3. showCount() ek static function hai jo class ke naam se directly call hota hai.

Real-Life Relevance

• Example:
  Agar tumhari MCA class me 60 students hain, aur har ek student ka ek roll number aur name alag hai.
  • Lekin total strength ek hi value hai (60).
  • Ye kaam static data member karta hai.

Conclusion

• Static data member sab objects ke liye common hota hai.
• Static functions bina object create kiye bhi call kiye ja sakte hain.
• Ye dono concept memory efficiency aur common properties track karne ke liye useful hain.

Submitted by:
Intesab Ansari
MCA Student, NMU University
Portfolio: intesab.live