Different forms of member functions

🔷 What is a Member Function?

A member function is a function declared inside a class. It operates on the data members of that class and defines the behavior of objects created from the class.

🔷 Different Forms of Member Functions in C++

Member functions can take various forms depending on how they are used and defined. Here’s a breakdown of the most commonly used forms:

🔶 1. Simple Member Function

A regular function that performs actions or returns values.

✅ Example:

class Student {
public:
    void display() {
        cout << "This is a simple member function." << endl;
    }
};

🔶 2. Parameterized Member Function

Takes parameters to work with different input values.

✅ Example:

class Student {
public:
    void setData(int roll, string name) {
        cout << "Roll No: " << roll << ", Name: " << name << endl;
    }
};

🔶 3. Return Type Member Function

Returns a value after performing a task.

✅ Example:

class Student {
public:
    int getRollNumber() {
        return 101;
    }
};

🔶 4. Inline Member Function

Defined inside the class, making it automatically inline (compiler may insert the function code directly into calling code for speed).

✅ Example:

class Student {
public:
    void show() {
        cout << "This is an inline function." << endl;
    }
};

🔶 5. Outside Class Definition (Using Scope Resolution Operator `::`)

Defined outside the class to keep class declaration clean and concise.

✅ Example:

class Student {
public:
    void display(); // Declared only
};

void Student::display() {
    cout << "Defined outside the class." << endl;
}

🔶 6. Const Member Function

Used when a function does not modify any data members. Useful for read-only operations.

✅ Example:

class Student {
public:
    int rollNo;

    int getRollNo() const {
        return rollNo;
    }
};

🔶 7. Static Member Function

Belongs to the class, not to any specific object. Can be called without creating an object. Can only access static members.

✅ Example:

class Student {
public:
    static void display() {
        cout << "Static function called." << endl;
    }
};

int main() {
    Student::display();  // Called without an object
}

🔶 8. Friend Function (Not technically a member)

A function declared as friend can access private/protected data of a class but is not a member of that class.

✅ Example:

class Student {
private:
    int rollNo = 101;

public:
    friend void showRoll(Student s);
};

void showRoll(Student s) {
    cout << "Roll No: " << s.rollNo << endl;
}

🔷 Summary Table

Form	Description	Access to Members	Called Using Object?
Simple	Regular function	Yes	Yes
Parameterized	Accepts parameters	Yes	Yes
Return Type	Returns values	Yes	Yes
Inline	Defined inside the class	Yes	Yes
Defined Outside Class	Defined outside using `::`	Yes	Yes
Const	Cannot modify members	Yes	Yes
Static	Belongs to class, not object	Only static	No (use ClassName)
Friend	External function with access to private data	Yes	No (called normally)

🔷 Summary

Member functions define object behavior.
They come in different forms: simple, parameterized, static, const, etc.
Some are used for data modification, others for read-only access or utility purposes.
Good design uses appropriate member function forms for clarity, safety, and performance.

Different forms of member functions

🔷 What is a Member Function?