Building Classes in C++ Introduction

The primary goal when building a class is to ensure encapsulation, which is the bundling of data (attributes) and methods (functions) that operate on that data into a single unit. To achieve encapsulation:

• Use access specifiers (private, protected, public) to restrict direct access to the class's internal state and expose only what is necessary.
• Provide controlled access through getter and setter methods to manipulate private data while maintaining constraints and validations.
• Encapsulation protects the integrity of an object by preventing external interference with its internal workings.

Example:

class Person {
private:
    std::string name;  // Private attribute
    int age;

public:
    // Constructor
    Person(const std::string& personName, int personAge) : name(personName), age(personAge) {}

    // Getter for name
    std::string getName() const {
        return name;
    }

    // Setter for name
    void setName(const std::string& newName) {
        name = newName;
    }

    // Method to display details
    void display() const {
        std::cout << "Name: " << name << ", Age: " << age << std::endl;
    }
};

Another important objective is designing classes to promote code reuse and modularity:

• Ensure the class is single-responsibility, meaning it should only perform tasks specific to its purpose.
• Focus on creating general-purpose classes that can be reused across different parts of the program.
• Group related functionalities within the same class, and keep unrelated functionalities in separate classes.

Modularity enables easier debugging, testing, and maintenance of code.

A developer should emphasize data abstraction, which involves exposing only essential features and hiding unnecessary details. The goal is to:

• Provide a clean and simple interface (e.g., public methods) to interact with the class.
• Hide implementation details so users of the class don’t need to understand its inner workings.

This makes the class easier to use and less prone to errors.

When designing classes, consider inheritance and polymorphism to extend functionality:

• Inheritance allows a new class to derive from an existing one, promoting code reuse.
• Polymorphism enables methods in derived classes to override base class methods, supporting dynamic behavior at runtime.

These features are especially important when designing frameworks or systems with interchangeable components.

Example:

class Animal {
public:
    virtual void sound() const {
        std::cout << "Animal makes a sound" << std::endl;
    }
};

class Dog : public Animal {
public:
    void sound() const override {
        std::cout << "Dog barks" << std::endl;
    }
};

When building classes, ensure they handle errors gracefully:

• Implement proper validation within setter methods to prevent invalid states.
• Use constructors to initialize attributes, ensuring objects are always in a valid state after creation.
• Employ exceptions for handling critical errors, such as invalid inputs or failed operations.

Efficient resource management is crucial, especially in C++:

• Use destructors to release dynamically allocated resources and avoid memory leaks.
• Leverage RAII (Resource Acquisition Is Initialization) principles to tie resource lifetimes to object lifetimes.
• Implement move semantics and use smart pointers where applicable to optimize memory usage and ownership management.