C++ Methods

In object-oriented programming (OOP), a method is a function that is associated with an object. It operates on the object's data and is defined within a class. In C++, methods are commonly referred to as member functions because they are members of a class. Here's an overview of methods in C++:

Class Definition with Methods:

#include <iostream>

// Class definition
class Calculator {
public:
    // Member function declaration
    int add(int a, int b);

    // Another member function declaration
    void displayResult(int result);
};

// Member function definition
int Calculator::add(int a, int b) {
    return a + b;
}

// Another member function definition
void Calculator::displayResult(int result) {
    std::cout << "Result: " << result << std::endl;
}

In this example, a class named Calculator is defined with two member functions: add and displayResult. These functions are declared within the class and defined outside of it.

Creating Objects and Calling Methods:

int main() {
    // Create an object of the Calculator class
    Calculator myCalculator;

    // Call the add method
    int sum = myCalculator.add(3, 4);

    // Call the displayResult method
    myCalculator.displayResult(sum);

    return 0;
}

In the main function, an object myCalculator of the Calculator class is created. The add and displayResult methods are then called on this object.

Access Control:

In the example above, the public keyword is used to specify that the member functions are accessible from outside the class. There are also private and protected access specifiers in C++.

class MyClass {
private:
    // Private members

public:
    // Public members

protected:
    // Protected members
};

Member Initialization List:

class Rectangle {
private:
    int length;
    int width;

public:
    // Constructor with member initialization list
    Rectangle(int l, int w) : length(l), width(w) {}

    // Other member functions
};

Static Member Functions:

class MathUtility {
public:
    // Static member function
    static int add(int a, int b);
};

// Definition of the static member function
int MathUtility::add(int a, int b) {
    return a + b;
}

int main() {
    // Call the static member function
    int result = MathUtility::add(3, 4);

    return 0;
}

Const Member Functions:

class Circle {
private:
    double radius;

public:
    // Constructor
    Circle(double r) : radius(r) {}

    // Const member function
    double getRadius() const {
        return radius;
    }
};

Understanding how to define and use methods is fundamental to working with classes and objects in C++. Methods encapsulate the behavior of objects and contribute to the overall structure and modularity of your code.