Question

此方法应将整个图书集添加到库对象书籍数组中。该方法必须在当前库的末尾添加新数组，并避免覆盖库中已有的任何书籍。确保包含每本书的一份副本。 [为简单起见，通过这种方法添加的书籍不会与彼此或以前的书籍重复]。

我试图编写的方法没有正确添加数组。这是缩短的库类。

public class Library { Book [] books; int [] copies; int [] checkedOut; int numBooks; public Library() { books = new Book[400];// Array to hold each book in element copies = new int[400];// Array to hold number of "book" copies corresponding to the element in the books array. checkedOut = new int[400];// Array to hold number of checked out books corresponding to the elemtn in the books array. numBooks = 0;// Number of unique books. } public void addMultipleBooks( Book [] b ) { for(int k = 0; k < b.length; k++) { for(int i = 0; i < books.length; i++) { if(books[i] == null) { numBooks = i; } books[numBooks] = b[k]; copies[numBooks] = copies[numBooks] + 1; } } } }// End Library Class

addMultipleBooks应该执行以下操作：

1）在数组中的正确位置添加每本新书。 2）将每本书的份数设置为1。 3）更新numBooks。

这里是主要的新书籍对象数组，我试图通过这个方法。

Book [] buildLibrary = new Book[10]; buildLibrary[0] = new Book( "Ulysses", new Author("Joyce","James") ); buildLibrary[1] = new Book( "The Great Gatsby", new Author("Fitzgerald","F. Scott") ); buildLibrary[2] = new Book( "A Portrait of the Artist as a Young Man", new Author("Joyce","James") ); buildLibrary[3] = new Book( "Lolita", new Author("Nobokov","Vladimir") ); buildLibrary[4] = new Book( "Brave New World", new Author("Huxley","Aldous") ); buildLibrary[5] = new Book( "The Sound and the Fury", new Author("Faulkner","William") ); buildLibrary[6] = new Book( "Catch-22", new Author("Heller","Joseph") ); buildLibrary[7] = new Book( "Darkness at Noon", new Author("Koestler","Arthur") ); buildLibrary[8] = new Book( "Sons and Lovers", new Author("Lawrence","D.H.") ); buildLibrary[9] = new Book( "The Grapes of Wrath", new Author("Steinbeck","John") );

不使用arraylists你可以使用以下代码，但我同意arraylists是最简单的方法。

public void addMultipleBooks(Book [] b) { for(int i = 0; i < b.length; i++) { books[numBooks] = b[i]; copies[numBooks]++; numBooks++; } }

Answer 1

无法更改数组的大小，因此您需要使用ArrayList而不是像Rohit Jain所说的那样，因为在添加和删除项目时可以扩展和缩短这些数据。

如果你想为它添加一个项目，你需要创建一个长度大于原始数组的全新数组，然后将所有原始数组项目移动到新数组中，然后移动新项目

是的，请使用ArrayList。

Answer 2

尝试修改代码以添加此方式：

for (int k = 0; k < b.length; k++) {
    for (int i = 0; i < books.length; i++) {
        if (books[i] == null) {
            numBooks = i;
            books[numBooks] = b[k];
            copies[numBooks] = copies[numBooks] + 1;
            break;
        }

    }
}

这样，只有当你的库中的书籍存储的当前插槽为空（null）时才会添加，然后继续进行下一个要添加的书籍项目（从库的书籍数组中搜索空槽开始）因为要存储的当前书已经找到了正确的插槽）

编写一个类方法，将数组添加到现有数组的空元素中

2 个答案: