Access specifiers

🧩 Part 1: Access Specifiers in C++

Access specifiers determine the visibility and accessibility of class members (variables and functions) to other parts of the program.

🔶 1. Public

• Members are accessible from anywhere (inside or outside the class).
• Used for interface functions that can be used by other classes or the main program.

✅ Example:

class Student {
public:
    int rollNo;
    void display() {
        cout << "Roll No: " << rollNo << endl;
    }
};

int main() {
    Student s;
    s.rollNo = 101;  // ✅ Allowed
    s.display();     // ✅ Allowed
}

---

🔶 2. Private

• Members are only accessible within the class.
• Cannot be accessed directly from outside the class.
• Ensures data hiding and security.

✅ Example:

class Student {
private:
    int rollNo;

public:
    void setRollNo(int r) {
        rollNo = r;
    }
    void display() {
        cout << "Roll No: " << rollNo << endl;
    }
};

int main() {
    Student s;
    // s.rollNo = 101; ❌ Not allowed (private)
    s.setRollNo(101);  // ✅ Allowed via public function
    s.display();       // ✅
}

---

🔶 3. Protected

• Similar to private, but accessible in derived classes (inheritance).
• Commonly used in inheritance scenarios.

✅ Example:

class Person {
protected:
    string name;

public:
    void setName(string n) {
        name = n;
    }
};

class Student : public Person {
public:
    void display() {
        cout << "Name: " << name << endl;  // ✅ Accessible in derived class
    }
};

int main() {
    Student s;
    s.setName("Alice");
    s.display();
}

---

🔷 Summary Table: Access Specifiers

Access Level	Inside Class	Outside Class	In Derived Class
public	✅ Yes	✅ Yes	✅ Yes
private	✅ Yes	❌ No	❌ No
protected	✅ Yes	❌ No	✅ Yes

---

🧩 Part 2: Array of Objects

An array of objects is a collection of multiple objects of the same class, stored in an array. It allows you to manage multiple instances efficiently.

✅ Syntax:

cppCopyEditClassName objectArray[array_size];

🔶 Example:

#include <iostream>
using namespace std;

class Student {
public:
    int rollNo;
    string name;

    void getData() {
        cout << "Enter roll number: ";
        cin >> rollNo;
        cout << "Enter name: ";
        cin >> name;
    }

    void display() {
        cout << "Roll No: " << rollNo << ", Name: " << name << endl;
    }
};

int main() {
    Student s[3];  // Array of 3 Student objects

    cout << "--- Enter Student Details ---" << endl;
    for (int i = 0; i < 3; i++) {
        s[i].getData();
    }

    cout << "\n--- Displaying Student Details ---" << endl;
    for (int i = 0; i < 3; i++) {
        s[i].display();
    }

    return 0;
}

---

🔷 Key Points:

• Each element in the array (s[0], s[1], s[2]) is a separate object.
• You can call member functions for each object using: cppCopyEdits[i].functionName();
• Useful when dealing with multiple records like students, employees, books, etc.

---

📌 Final Summary

✅ Access Specifiers:

• public: accessible everywhere
• private: only inside the class
• protected: class + derived classes

✅ Array of Objects:

• A collection of multiple class objects.
• Use loops to handle object input/output efficiently.
• Helps in building programs that manage lists of entities.