Interface-like behavior in C++ - Mini Project: Build & Apply

Interface-like Behavior in C++

📖 Scenario: Imagine you are building a simple program to manage different types of devices that can be turned on and off. Each device should have a way to turn it on and off, but the exact way might be different for each device.

🎯 Goal: You will create a basic interface-like behavior in C++ using abstract classes. You will define a class with pure virtual functions and then create classes that implement these functions. Finally, you will use these classes to turn devices on and off.

📋 What You'll Learn

Create an abstract class called Device with two pure virtual functions: turnOn() and turnOff().

Create a class called Light that inherits from Device and implements turnOn() and turnOff().

Create a class called Fan that inherits from Device and implements turnOn() and turnOff().

Create a pointer of type Device* to point to objects of Light and Fan and call their turnOn() and turnOff() methods.

Print messages to show which device is turning on or off.

💡 Why This Matters

🌍 Real World

Many programs use interface-like behavior to handle different objects in a uniform way, such as controlling various hardware devices or managing different types of user inputs.

💼 Career

Understanding abstract classes and polymorphism is essential for software development jobs, especially in C++ programming for systems, games, and applications requiring flexible design.

1

Create the abstract class Device

Create an abstract class called Device with two pure virtual functions: turnOn() and turnOff(). Both functions should return void and have no parameters.

C++

// Define the abstract class Device with pure virtual functions turnOn() and turnOff()
// Your code here

Need a hint?

Use virtual keyword and = 0 to make functions pure virtual.

2

Create the Light class inheriting Device

Create a class called Light that inherits from Device. Implement the turnOn() method to print "Light is turned ON" and the turnOff() method to print "Light is turned OFF".

C++

#include 

class Device {
public:
    virtual void turnOn() = 0;
    virtual void turnOff() = 0;
    virtual ~Device() = default;
};

// Define class Light inheriting Device and implement turnOn() and turnOff()
// Your code here

Need a hint?

Use override keyword to show you are implementing the base class methods.

3

Create the Fan class inheriting Device

Create a class called Fan that inherits from Device. Implement the turnOn() method to print "Fan is turned ON" and the turnOff() method to print "Fan is turned OFF".

C++

#include 

class Device {
public:
    virtual void turnOn() = 0;
    virtual void turnOff() = 0;
    virtual ~Device() = default;
};

class Light : public Device {
public:
    void turnOn() override {
        std::cout << "Light is turned ON" << std::endl;
    }
    void turnOff() override {
        std::cout << "Light is turned OFF" << std::endl;
    }
};

// Define class Fan inheriting Device and implement turnOn() and turnOff()
// Your code here

Need a hint?

Follow the same pattern as the Light class for Fan.

4

Use Device pointers to control Light and Fan

Create a Device* pointer called device. Point it to a Light object and call turnOn() and turnOff(). Then point device to a Fan object and call turnOn() and turnOff(). Print the output.

C++

#include 

class Device {
public:
    virtual void turnOn() = 0;
    virtual void turnOff() = 0;
    virtual ~Device() = default;
};

class Light : public Device {
public:
    void turnOn() override {
        std::cout << "Light is turned ON" << std::endl;
    }
    void turnOff() override {
        std::cout << "Light is turned OFF" << std::endl;
    }
};

class Fan : public Device {
public:
    void turnOn() override {
        std::cout << "Fan is turned ON" << std::endl;
    }
    void turnOff() override {
        std::cout << "Fan is turned OFF" << std::endl;
    }
};

// Create a Device* pointer called device
// Point it to Light and call turnOn() and turnOff()
// Point it to Fan and call turnOn() and turnOff()
// Your code here

Need a hint?

Use a pointer of type Device* to point to objects of Light and Fan. Call their methods using the pointer.