《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：

// 8.5 Deign a class for an online book reader system.
#include <unordered_map>
using namespace std;

class BookReaderSystem {
public:
    BookReaderSystem() {};
    
    // find a book by its name and read it.
    void readBook(string book_name) {
        Page page;
        
        if (books.find(book_name) != books.end()) {
            i = 0;
            // load the book page by page
            while (page = loadPage(books[book_name], i, page)) {
                displayPage(page);
                ++i;
            }
        }
    };
    
    ~BookReaderSystem() {
        books.clear();
    };
private:
    // the K-V database
    unordered_map<string, Book> books;
    // load one page from a book
    bool loadPage(Book &book, int page_no, Page &page);
    // display this page
    void displayPage(Page &page);
};