Summary  
This chapter explains how to declare class attributes (properties or fields) to define object state and how to access public attributes and methods on an object using the dot operator.

General domain of usage  
Object-oriented data modeling in applications.

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Public attributes and methods in a class can be **directly accessed using the dot operator** (`.`) **on an object** of the class. 

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The `public` keyword makes class members accessible from outside the class, which is why it's used here. This concept will be explained in more detail later.

Note

#define CATCH_CONFIG_MAIN
#include <catch2/catch.hpp>
#include <string>

// ÐÐ»Ð°ÑÑ Ð¸ ÑÑÐ½ÐºÑÐ¸Ñ Ð´Ð»Ñ ÑÐµÑÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð¸Ñ
class User {
public:
    std::string name;
    int age;
    bool isAdult;
};

User registerUser(const std::string& name, int age);

TEST_CASE("Register user aged 20 => isAdult true", "[registerUser]") {
    std::string name = "Alice";
    int age = 20;

    User user = registerUser(name, age);

    REQUIRE(user.name == "Alice");
    REQUIRE(user.age == 20);
    REQUIRE(user.isAdult == true);
}

TEST_CASE("Register user aged 18 => isAdult true", "[registerUser]") {
    std::string name = "Bob";
    int age = 18;

    User user = registerUser(name, age);

    REQUIRE(user.name == "Bob");
    REQUIRE(user.age == 18);
    REQUIRE(user.isAdult == true);
}

TEST_CASE("Register user aged 17 => isAdult false", "[registerUser]") {
    std::string name = "Charlie";
    int age = 17;

    User user = registerUser(name, age);

    REQUIRE(user.name == "Charlie");
    REQUIRE(user.age == 17);
    REQUIRE(user.isAdult == false);
}

TEST_CASE("Register user aged 0 => isAdult false", "[registerUser]") {
    std::string name = "Baby";
    int age = 0;

    User user = registerUser(name, age);

    REQUIRE(user.name == "Baby");
    REQUIRE(user.age == 0);
    REQUIRE(user.isAdult == false);
}

TEST_CASE("Register user with empty name => isAdult depends on age", "[registerUser]") {
    std::string name = "";
    int age = 25;

    User user = registerUser(name, age);

    REQUIRE(user.name == "");
    REQUIRE(user.age == 25);
    REQUIRE(user.isAdult == true);
}

test.cpp

Object-Oriented Programming (OOP) in C++ helps you build clean, reusable, and scalable code by organizing programs around objects and classes. You’ll learn how to define and use classes, create constructors and destructors, and apply encapsulation to protect data. Topics like inheritance, polymorphism, static members, access control, and operator overloading will help you design flexible and efficient code structures. 

Learn how to create classes and objects, define attributes and methods, work with static members and the this keyword. Gain a solid foundation in how objects interact and how to write clean, modular code using OOP principles.

Learn how constructors and destructors manage object creation and cleanup. Practice using initialization lists, constructor delegation, and writing clean, efficient code with proper object lifecycle handling.

Learn how encapsulation, one of OOP's core principles, improves code modularity and maintainability through data hiding, access control, and the use of accessor and mutator methods.

Learn about fundamental mechanism of object-oriented programming that enables code reuse and promotes the creation of hierarchical relationships among classes.

Polymorphism is a foundational concept in OOP that enables the creation of flexible and extensible code structures. You will learn about virtual function, abstract classes and operator overloading and their pivotal roles in promoting code flexibility and scalability.

Challenge: Attributes of the Class

Solution