public class BooksTestDrive {
public static void main(String[] args) {
Books [] myBooks = new Books[3];
int x=0;
myBooks[0].title = "The Grapes of Jave";
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;
}
}
}
该代码可以编译,但在运行时会给出nullpointer异常。
最佳答案
您对MyBooks [3]的分配仅分配了数组。您仍然需要为数组中的每个条目分配一个“ new MyBook()”。