OOP — Classes & Inheritance

#include <iostream>
#include <string>
using namespace std;

class Student {
private:                    // बाहेरून direct access नाही
    string name;
    int marks;

public:                     // बाहेरून access होते
    // Constructor — object बनवताना call होतो
    Student(string n, int m) : name(n), marks(m) {}

    // Default constructor
    Student() : name("Unknown"), marks(0) {}

    // Getter methods
    string getName()  const { return name; }
    int    getMarks() const { return marks; }

    // Setter
    void setMarks(int m) {
        if (m >= 0 && m <= 100) marks = m;
    }

    // Method
    string getResult() const {
        return marks >= 40 ? "Pass ✅" : "Fail ❌";
    }

    // Display
    void display() const {
        cout << name << " — " << marks
             << " (" << getResult() << ")" << endl;
    }
};

int main() {
    Student s1("Rahul", 85);
    Student s2("Priya", 35);
    Student s3;   // default constructor

    s1.display();   // Rahul — 85 (Pass ✅)
    s2.display();   // Priya — 35 (Fail ❌)

    s1.setMarks(92);
    cout << s1.getName() << ": " << s1.getMarks() << endl;

    return 0;
}

class Animal {
protected:
    string name;

public:
    Animal(string n) : name(n) {}

    void eat() {
        cout << name << " खातो." << endl;
    }

    virtual void speak() {  // virtual — runtime polymorphism
        cout << name << " आवाज करतो." << endl;
    }
};

// Single inheritance
class Dog : public Animal {
public:
    Dog(string n) : Animal(n) {}  // parent constructor call

    void speak() override {       // override — parent method replace
        cout << name << " भुंकतो: Woof! 🐕" << endl;
    }

    void fetch() {
        cout << name << " ball आणतो!" << endl;
    }
};

class Cat : public Animal {
public:
    Cat(string n) : Animal(n) {}

    void speak() override {
        cout << name << " म्हणतो: Meow! 🐱" << endl;
    }
};

int main() {
    Dog d("Bruno");
    Cat c("Whiskers");

    d.speak();   // Bruno भुंकतो: Woof! 🐕
    d.eat();     // Bruno खातो. — inherited
    d.fetch();

    c.speak();   // Whiskers म्हणतो: Meow! 🐱

    // Polymorphism — base pointer, derived objects
    Animal *a1 = new Dog("Rex");
    Animal *a2 = new Cat("Luna");

    a1->speak();  // Rex भुंकतो (Dog's speak!)
    a2->speak();  // Luna म्हणतो (Cat's speak!)

    delete a1; delete a2;
    return 0;
}