Java 学习笔记 (六) Java 定义变量

这个问题来自于head first一书page68.

 package com.idea.study;
 
 public class Books {   //headfirst page68
     String title;   //为什么要写在这里？写在方法里就不行？
     String author;
     public static void main(String[] args){
         Books[] myBooks = new Books[3];
         int x=0;
         myBooks[0] = new Books();
         myBooks[1] = new Books();
         myBooks[2] = new Books();
         myBooks[0].title = "The Grapes of Java";
         myBooks[1].title = "The Java Gatsby";
         myBooks[2].title = "The Java Cookbook";
         myBooks[0].author = "bob";
         myBooks[1].author = "sue";
         myBooks[2].author = "ian";
         while(x<3){
             System.out.print(myBooks[x].title);
             System.out.print(" by ");
             System.out.println(myBooks[x].author);
             x=x+1;
         }
 
     }
 }