在 Java 中对对象数组进行冒泡排序
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Bubble sorting an object array in Java
提问by Aiden O'Jester
how do I sort an array of objects? this is my code for sorting the array, I receive a "not a statement" error for: Movie temp = movies[b]; what do i declare the temp variable as if it is to hold the exact value/reference of movies[b]; which could be any of three different object types which are in the same array? I am new to programming so I apologize if i seem to be ignorant; please feel free to correct me or ask questions if I phrased the questions incorrectly.
如何对对象数组进行排序？这是我对数组进行排序的代码，我收到一个“not a statement”错误： Movie temp = movies[b]; 我如何声明临时变量，就好像它要保存电影的确切值/引用[b]；哪个可能是同一数组中的三种不同对象类型中的任何一种？我是编程新手，如果我似乎无知，我深表歉意；如果我的问题措辞不正确，请随时纠正我或提出问题。
public static String bubbleSort(Movie[] movies) {
for (int a=1; a<movies.length; a++) {
for(int b=0; b<movies.length - a; b++) {
if (((movies[b].getTitle()).compareTo((movies[b+1].getTitle()))) > 0)
//swap movies[b] with movies[b+1]
Movie temp = movies[b];
movies[b] = movies[b+1];
movies[b+1] = temp;
}
}
}
回答by Dave
When an array is defined as Movie[]it can only contains objects of type Movie. So you can only have Movies in there. However, to make this general, you should define the type as Objectand the array as Object[].
当一个数组被定义为Movie[]它只能包含类型的对象时Movie。所以你只能Movie在那里有s 。但是，为了使其通用，您应该将类型定义为Object并将数组定义为Object[]。
However, in your code, you are assuming that you really do have Movieobjects because you're using Movie.getTitle(). You will not be able to access that from references of Object. I would recommend having your objects implement Comparableand using the type Comparableas the type of the array and your temporary variable.
但是，在您的代码中，您假设您确实拥有Movie对象，因为您使用的是Movie.getTitle(). 您将无法从 的引用访问它Object。我建议让您的对象实现Comparable并使用该类型Comparable作为数组和临时变量的类型。
回答by Jim Garrison
The Movie temp = movies[b];is a declaration, not a statement. You want this:
该Movie temp = movies[b];是一个声明，而不是一个声明。你要这个：
if (((movies[b].getTitle()).compareTo((movies[b+1].getTitle()))) > 0)
{
//swap movies[b] with movies[b+1]
Movie temp = movies[b];
movies[b] = movies[b+1];
movies[b+1] = temp;
}
Note all I did was add braces around all the swap code, making it into a block which cancontain a declaration. I think this is what you intended, but just omitted the braces.
请注意，我所做的只是在所有交换代码周围添加大括号，使其成为一个可以包含声明的块。我认为这就是您的意图，但只是省略了大括号。
回答by Janek Bogucki
You were missing a { after the test, and incorrectly promising to return a String. Try this,
您在测试后遗漏了一个 {，并且错误地承诺返回一个字符串。试试这个，
public static void bubbleSort(Movie[] movies) {
for (int a = 1; a < movies.length; a++) {
for (int b = 0; b < movies.length - a; b++) {
if (((movies[b].getTitle())
.compareTo((movies[b + 1].getTitle()))) > 0) {
// swap movies[b] with movies[b+1]
Movie temp = movies[b];
movies[b] = movies[b + 1];
movies[b + 1] = temp;
}
}
}
}
回答by Manfred Moser
Use the Collections api and dont reinvent the wheel doing your own sorting implementation.
使用 Collections api，不要重新发明轮子做你自己的排序实现。
