我已经分配了基于以下方式开发简单Java程序的任务：
写算法以搜索保留书籍副本，从列表中 (数组(使用线性搜索的书籍，然后将它们存储在 使用插入算法的新创建的数组的开始。
我已经写了算法，但是由于以下代码的最后一行的问题，我正在努力证明它：
package javaapplicationadt2;
public class Books
{
public String ISBN; // class properties
public String title;
public int copies;
boolean reserved = true;
public static void main(String[] args)
{
Books[] Book1 = new Books[1];
Books[] Book2 = new Books[1];
Book1[0].ISBN = "ISBN-00001";
Book1[0].title = "Algorithms that torture minds";
Book1[0].copies = 2;
Book1[0].reserved = true;
Book2[0].ISBN = "ISBN-00002";
Book2[0].title = "Lecture Slides that defied practical Java Programming !";
Book2[0].copies = 1;
Book2[0].reserved = false;
for (int i = 0; i < Book1.length; i++)
if (Book1[i].reserved = true)
for (int j = Book2.length - 1; j > 0; j++)
Book2[j] = Book2[j - 1];
*Book2[0] = Book1[i].title;* **(Incompatible types:
Books cannot be converted to a String)**
}
}
您的逻辑和代码约定有很多错误
java使用骆驼作为编写方法，变量，类，软件包和常数的命名。班级名称应为名词，在混合情况下，每个内部单词都大写的第一个字母。接口名称也应像班级名称一样大写。看看Java代码约定
Book[] bookArray = new Book[1];
回到您的代码。当你做
时Book[] book1 = new Book[1]; //Create an Array of Books -> all elements are NULL
book1[0].ISBN = "ISBN-00001"; // book1[0] is NULL so a NullPointException will be throw
您必须初始化数组和/或将对象分配给它
Book[] bookArray = new Book[1];
Book book = new Book();
Book[0] = book; //Now you have an Object Book at Book[0] and you can set the properties
bookArray[0].ISBN = "ISBN-00001";
对于...如果...如果不定义块，则仅执行下一行。即。
if(true == bookArray[0].reserved)
System.out.println("1");//This will be executed only if condition is true
System.out.println("2"); //This will be executed no matter what
如果您只想在条件为真时执行代码，则必须：
if(true == bookArray[0].reserved){
System.out.println("1");//This will be executed only if condition is true
System.out.println("2"); //This will be executed only if condition is true
}