MVC (Model-View-Controller)

MVC (Model-View-Controller) is a design pattern used in software development to separate concerns within an application. It is commonly used in GUI applications, web development, and game engines.


🔹 Components of MVC

MVC is divided into three key components:

  1. Model (M) – Handles the data and business logic.
  2. View (V) – Handles the UI and displays data.
  3. Controller (C) – Acts as an intermediary between the Model and View.
ComponentResponsibility
ModelManages application data, business logic, and state.
ViewDisplays the data to the user and handles user interface updates.
ControllerHandles user input and updates the Model or View accordingly.

🔹 Why Use MVC?

Separation of Concerns – Each component has a distinct role, making code modular and maintainable.
Scalability – Easy to extend and modify without affecting the whole system.
Reusability – Views and models can be reused across different applications.
Testability – Each part can be tested independently.


🔹 Example: MVC in C++

Let’s implement a simple C++ MVC application that manages user information.

1. Model (Handles Data & Business Logic)

// Model.h
#ifndef MODEL_H
#define MODEL_H
#include <string>

class Model {
private:
    std::string userName;
public:
    void setUserName(const std::string& name) { userName = name; }
    std::string getUserName() const { return userName; }
};

#endif // MODEL_H

2. View (Handles UI & Display)

// View.h
#ifndef VIEW_H
#define VIEW_H
#include <iostream>
#include <string>

class View {
public:
    void displayUser(const std::string& name) {
        std::cout << "User Name: " << name << std::endl;
    }
};

#endif // VIEW_H

3. Controller (Handles Input & Updates Model/View)

// Controller.h
#ifndef CONTROLLER_H
#define CONTROLLER_H
#include "Model.h"
#include "View.h"

class Controller {
private:
    Model& model;
    View& view;
public:
    Controller(Model& m, View& v) : model(m), view(v) {}

    void setUserName(const std::string& name) {
        model.setUserName(name);
    }

    void updateView() {
        view.displayUser(model.getUserName());
    }
};

#endif // CONTROLLER_H

4. Main Function (Tying Everything Together)

// main.cpp
#include "Model.h"
#include "View.h"
#include "Controller.h"

int main() {
    Model model;
    View view;
    Controller controller(model, view);

    controller.setUserName("Alice");
    controller.updateView();

    return 0;
}


🔹 How It Works?

  1. The Model (Model.h) stores the user’s name.
  2. The View (View.h) is responsible for displaying the user’s name.
  3. The Controller (Controller.h) acts as a middleman:
    • It updates the model with a new user name.
    • It tells the view to display the updated name.
  4. The Main Function creates objects of Model, View, and Controller, then sets the user’s name and updates the display.

🔹 Advantages of Using MVC in C++

  • Code Maintainability – Easily modify UI (View) without affecting the Model.
  • Flexibility – Change the business logic without modifying the UI.
  • Improved Testing – Since the Model and Controller are independent, they can be tested separately.

🔹 When to Use MVC in C++?

  • GUI Applications (Qt, MFC, FLTK)
  • Game Development (Unreal Engine, Unity with C++)
  • Web Frameworks (C++ Backends like Wt)
  • Large Applications that need a clean separation of concerns.

🔹 Summary

  • Model (M) → Handles data & business logic.
  • View (V) → Manages UI & data presentation.
  • Controller (C)Processes user input & updates Model/View.

By using MVC, we create a structured, reusable, and scalable application architecture in C++.