Runtime polymorphism in C++ - Mini Project: Build & Apply

Runtime Polymorphism in C++

📖 Scenario: You are creating a simple program to demonstrate how different animals make different sounds. Each animal has a method to make a sound, but the exact sound depends on the animal type.

🎯 Goal: Build a C++ program that uses runtime polymorphism to call the correct makeSound() method for different animal objects.

📋 What You'll Learn

Create a base class called Animal with a virtual method makeSound().

Create two derived classes Dog and Cat that override makeSound().

Use a pointer of type Animal* to call makeSound() on objects of Dog and Cat.

Print the sounds made by the dog and cat.

💡 Why This Matters

🌍 Real World

Runtime polymorphism helps programs decide which method to run while the program is running, like choosing the right animal sound depending on the animal.

💼 Career

Understanding runtime polymorphism is essential for writing flexible and maintainable object-oriented code used in software development jobs.

1

Create the base class Animal

Write a class called Animal with a public virtual method makeSound() that prints "Some generic animal sound".

C++

// Your code here

Need a hint?

Use virtual keyword before makeSound() to allow overriding.

2

Create derived classes Dog and Cat

Add two classes Dog and Cat that inherit from Animal. Override makeSound() in Dog to print "Woof!" and in Cat to print "Meow!".

C++

#include 
using namespace std;

class Animal {
public:
    virtual void makeSound() {
        cout << "Some generic animal sound" << endl;
    }
};

// Your code here

Need a hint?

Use override keyword to clearly show you are overriding the base class method.

3

Use Animal pointers to call makeSound()

Create two pointers of type Animal*, one pointing to a Dog object and the other to a Cat object. Use these pointers to call makeSound().

C++

#include 
using namespace std;

class Animal {
public:
    virtual void makeSound() {
        cout << "Some generic animal sound" << endl;
    }
};

class Dog : public Animal {
public:
    void makeSound() override {
        cout << "Woof!" << endl;
    }
};

class Cat : public Animal {
public:
    void makeSound() override {
        cout << "Meow!" << endl;
    }
};

// Your code here

Need a hint?

Use new to create objects and call makeSound() through pointers.

4

Print the sounds made by Dog and Cat

Add cout statements to print the sounds made by the dog and cat when calling makeSound(). Run the program to see the output.

C++

#include 
using namespace std;

class Animal {
public:
    virtual void makeSound() {
        cout << "Some generic animal sound" << endl;
    }
};

class Dog : public Animal {
public:
    void makeSound() override {
        cout << "Woof!" << endl;
    }
};

class Cat : public Animal {
public:
    void makeSound() override {
        cout << "Meow!" << endl;
    }
};

int main() {
    Animal* animal1 = new Dog();
    Animal* animal2 = new Cat();

    // Your code here

    delete animal1;
    delete animal2;
    return 0;
}

Need a hint?

Running the program should print Woof! and Meow! on separate lines.