In C++, classes are used to define objects, and methods (also called member functions) define the behavior of these objects. Class methods operate on the data contained in the object and help perform tasks specific to that object. This blog will guide you through the concept of class methods in C++, how to define them, call them, and best practices when working with them.

What Are Class Methods?

Class methods in C++ are functions that are defined inside a class. These methods can access and modify the class's attributes (also known as data members). Methods are fundamental to object-oriented programming as they allow objects to interact and perform actions.

Defining a Class Method

There are two ways to define class methods in C++:

• Inside the class definition
• Outside the class definition using the scope resolution operator ::

Example: Method Defined Inside the Class

    #include <iostream>
    using namespace std;

    class Car {
    public:
        void startEngine() {
            cout << "Engine started!" << endl;
        }
    };

    int main() {
        Car myCar;
        myCar.startEngine();
        return 0;
    }
    

In this example, startEngine() is a method defined inside the class Car.

Example: Method Defined Outside the Class

    #include <iostream>
    using namespace std;

    class Car {
    public:
        void startEngine();  // Declaration
    };

    // Definition outside the class
    void Car::startEngine() {
        cout << "Engine started from outside definition!" << endl;
    }

    int main() {
        Car myCar;
        myCar.startEngine();
        return 0;
    }
    

Here, the method startEngine() is defined outside the class using the scope resolution operator Car::.

Calling Class Methods

To call a class method, you must first create an object of the class. Then use the dot operator (.) to call the method.

    myCar.startEngine();
    

This statement tells the compiler to call the startEngine() method on the myCar object.

Accessing Data Members with Methods

Class methods are often used to access or modify private data members of a class. This is part of encapsulation, which keeps the data safe and controlled.

    class Car {
    private:
        int speed;

    public:
        void setSpeed(int s) {
            speed = s;
        }

        int getSpeed() {
            return speed;
        }
    };
    

Here, setSpeed() and getSpeed() are public methods that allow controlled access to the private member speed.

Best Practices for Using Class Methods

• Keep your methods short and focused on a single task.
• Use meaningful method names that describe what the method does.
• Encapsulate access to private data through public getter and setter methods.
• Group related methods logically within the class structure.

Conclusion

Class methods in C++ are essential for defining the behavior of objects. By using methods, you can create well-structured, reusable, and maintainable code. Whether defined inside or outside the class, methods are a core part of object-oriented programming that help bring your C++ applications to life.