《Cracking the Coding Interview》——第8章：面向对象设计——题目5

2014-04-23 18:42

题目：设计一个在线阅读系统的数据结构。

解法：这题目太大了，我的个亲娘。显然你不可能一次加载一整本书，做到单页纸加载的粒度是很必要的。为了读书的连贯效果，预取个几页也很必要。

代码：

 1 // 8.5 Deign a class for an online book reader system.

 2 #include <unordered_map>

 3 using namespace std;

 4 

 5 class BookReaderSystem {

 6 public:

 7     BookReaderSystem() {};

 8     

 9     // find a book by its name and read it.

10     void readBook(string book_name) {

11         Page page;

12         

13         if (books.find(book_name) != books.end()) {

14             i = 0;

15             // load the book page by page

16             while (page = loadPage(books[book_name], i, page)) {

17                 displayPage(page);

18                 ++i;

19             }

20         }

21     };

22     

23     ~BookReaderSystem() {

24         books.clear();

25     };

26 private:

27     // the K-V database

28     unordered_map<string, Book> books;

29     // load one page from a book

30     bool loadPage(Book &book, int page_no, Page &page);

31     // display this page

32     void displayPage(Page &page);

33 };