Constructor overloading in C++ - Mini Project: Build & Apply

Constructor overloading

📖 Scenario: Imagine you are creating a simple program to manage information about books in a library. Each book can be created with different details depending on what information you have.

🎯 Goal: You will build a Book class with multiple constructors that allow creating book objects in different ways. This is called constructor overloading.

📋 What You'll Learn

Create a Book class with overloaded constructors

One constructor should take no arguments and set default values

One constructor should take the book title as a std::string

One constructor should take the book title and author as std::string

Create objects using each constructor

Print the book details to show the constructor used

💡 Why This Matters

🌍 Real World

Constructor overloading is useful when you want to create objects flexibly depending on how much information you have. For example, a library system might create book records with just a title or with full details.

💼 Career

Understanding constructor overloading is important for software developers working with object-oriented languages like C++. It helps write clean, flexible, and easy-to-use classes.

1

Create the Book class with default constructor

Write a Book class with a default constructor that sets title to "Unknown" and author to "Unknown". Declare title and author as std::string members.

C++

#include 
#include 

// Define Book class with default constructor
// Your code here

Need a hint?

Remember to include std::string members and write a constructor with no parameters that sets default values.

2

Add constructor with title parameter

Add a constructor to the Book class that takes a std::string parameter called title and sets the title member to it. Set author to "Unknown" inside this constructor.

C++

#include 
#include 

class Book {
public:
    std::string title;
    std::string author;

    Book() {
        title = "Unknown";
        author = "Unknown";
    }

    // Add constructor with title parameter here
    // Your code here
};

Need a hint?

Use this->title = title; to set the member variable inside the constructor.

3

Add constructor with title and author parameters

Add another constructor to the Book class that takes two std::string parameters: title and author. Set the class members title and author to these parameters.

C++

#include 
#include 

class Book {
public:
    std::string title;
    std::string author;

    Book() {
        title = "Unknown";
        author = "Unknown";
    }

    Book(std::string title) {
        this->title = title;
        author = "Unknown";
    }

    // Add constructor with title and author parameters here
    // Your code here
};

Need a hint?

Use this-> to assign both title and author inside the constructor.

4

Create objects and print their details

In the main function, create three Book objects: book1 using the default constructor, book2 using the constructor with title "1984", and book3 using the constructor with title "The Hobbit" and author "J.R.R. Tolkien". Then print the details of each book in the format: Title: [title], Author: [author].

C++

#include 
#include 

class Book {
public:
    std::string title;
    std::string author;

    Book() {
        title = "Unknown";
        author = "Unknown";
    }

    Book(std::string title) {
        this->title = title;
        author = "Unknown";
    }

    Book(std::string title, std::string author) {
        this->title = title;
        this->author = author;
    }
};

int main() {
    // Create book1, book2, book3
    // Print their details
    // Your code here
}

Need a hint?

Create the three Book objects using the correct constructors and print their details using std::cout.