Learn The This Keyword | Fundamentals of OOP in C++

The this keyword in object-oriented programming refers to the current object instance. It provides member functions with a pointer to the object that invoked them, allowing access to that object's variables and functions.

Example.cpp


              12345678910111213
            
#include <iostream>

class Example {
public:
    Example* get_address() { return this; }
};

int main()
{
    Example obj;
    std::cout << &obj << std::endl;
    std::cout << obj.get_address() << std::endl;
}

When you use the dot operator (.) to access member variables or member functions within a class, the this pointer implicitly points to the object for which the member function is called. This is often valuable in various scenarios and commonly employed to avoid ambiguity in variable names.

Example.cpp


              123456789101112131415
            
#include <iostream>

class Example {
public:
    void multiply(int number) { number *= number; }
    int number;
};

int main()
{
    Example obj;
    obj.number = 2;
    obj.multiply(5);
    std::cout << obj.number;
}

Here, we can utilize the this keyword since it points to the current object as a pointer. To access its attributes, we must use the -> operator.

main.cpp


              123456789101112131415
            
#include <iostream>

class Example {
public:
    void multiply(int number) { this->number *= number; }
    int number;
};

int main()
{
    Example obj;
    obj.number = 2;
    obj.multiply(5);
    std::cout << obj.number;
}

Using the this keyword is a widespread practice across various scenarios. It's often employed, particularly in large classes, to signify that a variable is a member of the classes and not an external parameter or argument.

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Section 1. Chapter 7

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Example.cpp


              12345678910111213
            
#include <iostream>

class Example {
public:
    Example* get_address() { return this; }
};

int main()
{
    Example obj;
    std::cout << &obj << std::endl;
    std::cout << obj.get_address() << std::endl;
}

Example.cpp


              123456789101112131415
            
#include <iostream>

class Example {
public:
    void multiply(int number) { number *= number; }
    int number;
};

int main()
{
    Example obj;
    obj.number = 2;
    obj.multiply(5);
    std::cout << obj.number;
}

Here, we can utilize the this keyword since it points to the current object as a pointer. To access its attributes, we must use the -> operator.

main.cpp


              123456789101112131415
            
#include <iostream>

class Example {
public:
    void multiply(int number) { this->number *= number; }
    int number;
};

int main()
{
    Example obj;
    obj.number = 2;
    obj.multiply(5);
    std::cout << obj.number;
}

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 7

The This Keyword

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The This Keyword