Q4. Demonstrate the Use of Inheritance

Question:
Write program(s) to demonstrate the use of inheritance.

My Approach

Inheritance C++ ka ek powerful concept hai jaha ek class (child/derived) doosri class (parent/base) ke properties aur methods ko inherit karti hai.
Ye reusability provide karta hai aur real-world modeling ke liye best hai.

Maine is example ke liye ek real-world Student and Result System banaya hai:

Base Class: Person → har person ka name aur age.
Derived Class 1: Student → Person se inherit karke rollNumber add karta hai.
Derived Class 2: Result → Student se inherit karke marks aur percentage calculate karta hai.

Program Code

File Name: inheritance_demo.cpp


#include <iostream>
using namespace std;
 
// Base Class
class Person {
protected:
    string name;
    int age;
public:
    Person(string n, int a) {
        name = n;
        age = a;
    }
 
    void displayPerson() {
        cout << "Name: " << name << endl;
        cout << "Age: " << age << endl;
    }
};
 
// Derived Class 1
class Student : public Person {
protected:
    int rollNumber;
public:
    Student(string n, int a, int r) : Person(n, a) {
        rollNumber = r;
    }
 
    void displayStudent() {
        displayPerson();
        cout << "Roll Number: " << rollNumber << endl;
    }
};
 
// Derived Class 2
class Result : public Student {
private:
    float marks1, marks2, marks3;
public:
    Result(string n, int a, int r, float m1, float m2, float m3) 
        : Student(n, a, r) {
        marks1 = m1;
        marks2 = m2;
        marks3 = m3;
    }
 
    void displayResult() {
        displayStudent();
        float total = marks1 + marks2 + marks3;
        float percentage = total / 3;
        cout << "Marks: " << marks1 << ", " << marks2 << ", " << marks3 << endl;
        cout << "Total: " << total << endl;
        cout << "Percentage: " << percentage << "%" << endl;
    }
};
 
int main() {
    Result r("Intesab Ansari", 23, 101, 78.5, 82.0, 90.0);
 
    cout << "=== Student Result Information ===" << endl;
    r.displayResult();
 
    return 0;
}

Sample Input / Output

Output:


=== Student Result Information ===
Name: Intesab Ansari
Age: 23
Roll Number: 101
Marks: 78.5, 82, 90
Total: 250.5
Percentage: 83.5%

Explanation

Person → Base class with common details (name, age).
Student → Derived from Person, adds rollNumber.
Result → Derived from Student, adds marks and percentage calculation.
Example me multi-level inheritance ka use hua hai.

Real Time Relevance

Education system me Person → Student → Result ek perfect real-world case hai.
Inheritance ka use har jagah hota hai jaha hierarchy design karni hoti hai, jaise Bank System (Account → Savings/Current), Company (Employee → Manager/Developer), etc.

Conclusion

Is program se inheritance ka real use samajh aata hai. Code reusability aur hierarchy design ke liye ye ek must-know concept hai.

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