Java Book类

package com.lq003;

import java.util.Scanner;
class Book {
    String title;
    String author;
    double price;

    public Book(String title, String author, double price) {
        this.title = title;
        this.author = author;
        this.price = price;
    }

    public Book() {
        this.title =" default";
        this.author = "noname";
        this.price =50.0;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }


    @Override
    public String toString() {
        return "("+title+","+author+","+price+")";
    }

}


public class BookApp {
    public static void main(String[] args) {
        Book book;
        Scanner scan=new Scanner(System.in);
        int sel;
        sel=scan.nextInt();
        switch (sel){
            case 1:
                book=new Book();
                book.setAuthor("ligang");
                book.setTitle("java");
                book.setPrice(101.8);
                System.out.println("Compile pass!");
                break;
            case 2:
                new Book("java", "lixianghua", 89.9);
                System.out.println("params constructor pass");
                break;
            case 3:
                book=new Book();
                book.setAuthor("Ligang");
                book.setTitle("JAVA");
                book.setPrice(101.8);
                System.out.println(book.getAuthor()+","+book.getTitle()+","+book.getPrice());
                break;
            case 4:
                book=new Book();
                System.out.println(book);
                break;
            case 5:
                book=new Book("C++","Tanhaoqiang",80);
                System.out.println(book);


                break;

        }
        scan.close();
    }
}