Model design
- C++ course
- Intermediate
- Lesson 65/116
- 6 min
Design the skeleton of Book and Member classes.
Project: Library app
In this 5-lesson project you will build a library application. Each lesson adds one piece, and by the final lesson you will have a working console app. Everything is built on the Book and Library classes.
You will use what you learned in previous groups: classes, constructors and iterators. In the first lesson you design the Book class skeleton: title and author fields are private, and getTitle() exposes them to callers. The starting code of the next lessons will contain this class.
Book class design
The Book class carries two private fields: title and author. The constructor (Book(std::string t, std::string a)) initializes them. The getTitle() and getAuthor() methods let callers read the values.
Example: Book b("Tutunamayanlar", "Oğuz Atay"); creates a book. b.getTitle() reads the title. The member initializer list (: title(t), author(a)) initializes fields efficiently. const methods do not modify the class; that is why getters are const.
Practice Define the Book class
Define a Book class. In the private section add std::string title and std::string author fields. In the public section add a constructor and a getTitle() method. In main, create a Book and print its title with std::cout.
Starter code
#include <iostream>
#include <string>
// Define the Book class here
int main() {
// Create a Book and print its title
return 0;
}Sample solution
#include <iostream>
#include <string>
class Book {
private:
std::string title;
std::string author;
public:
Book(std::string t, std::string a) : title(t), author(a) {}
std::string getTitle() const { return title; }
std::string getAuthor() const { return author; }
};
int main() {
Book b("Tutunamayanlar", "Oğuz Atay");
std::cout << b.getTitle();
return 0;
}Expected output
Tutunamayanlar
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which member should be private?
class Book {
???
std::string title;
};- the getTitle method
- the main function
- the title field Correct answer
- std::cout
Explanation: Data fields are private, accessor methods are public.
2 Call the getter method
Book b("Tutunamayanlar", "Oğuz Atay");
std::cout << b.____();Book b("Tutunamayanlar", "Oğuz Atay");
std::cout << b.getTitle();Explanation: b.getTitle() reads the title.
3 Match each member to its role
| Term | Meaning |
|---|---|
std::string title |
Private data |
Book(std::string, std::string) |
Constructor |
std::string getTitle() |
Getter method |
const |
No-modify marker |