在 Java 中创建对象类数组的实例
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Creating an instance of an array of objects class in Java
提问by singmotor
I'm new to Java, and I'm getting an error in my main function when I try to create an instance of a DeckofCards class. The DeckofCards class is supposed to be a private array of "Cards" objects. I think my issue is something in the DeckofCards class, for some reason it's not an array I think? Maybe I created it wrong?
我是 Java 新手，当我尝试创建 DeckofCards 类的实例时，我的主函数出现错误。DeckofCards 类应该是“卡片”对象的私有数组。我认为我的问题出在 DeckofCards 类中，出于某种原因，我认为它不是数组？也许我创建错了？
The errors in my main are '(' or '[' expectedand array required but DeckofCards found
我的主要错误是 '(' 或 '[' 预期和 数组，但发现 DeckofCards
Here is my main function:
这是我的主要功能：
public static void main(String[] args) {
Card myCard = new Card(13,1);
System.out.println(myCard.getSuit());
System.out.println(myCard);
DeckofCards myDeck = new DeckofCards; //error here
for(int i=0; i<53; i++) {
System.out.println(myDeck[i]); //second error here
}
}
Here is my DeckofCards class:
这是我的 DeckofCards 课程：
public class DeckofCards {
private Card[] deck = new Card[52];
public DeckofCards(){
int i = 0;
for(int s = 1; s<5; s++){
for(int r = 1; r<14; r++){
deck[i].rank = r;
deck[i].suit = s;
i++;
}
}
}
}
If anyone can tell me if I'm missing some syntax or something that'd be great! Thank you.
如果有人能告诉我我是否遗漏了一些语法或一些很棒的东西！谢谢你。
采纳答案by Ted Hopp
You need to call the constructor:
您需要调用构造函数：
DeckofCards myDeck = new DeckofCards(); // note parens!
In Java, the parentheses are required.
在 Java 中，括号是必需的。
In the constructor, you will also need to initialize each element of the array to a new Cardobject:
在构造函数中，您还需要将数组的每个元素初始化为一个新Card对象：
for(int s = 1; s<5; s++){
for(int r = 1; r<14; r++){
deck[i] = new Card();
deck[i].rank = r;
deck[i].suit = s;
i++;
回答by Reimeus
The error is pretty clear, myDeckis a single custom Objectrather than an array
错误很明显，myDeck是单个自定义Object而不是数组
DeckofCards myDeck = new DeckofCards(); // parenthesis here
for (int i=0; i<53; i++) {
System.out.println(myDeck); // no brackets here
}
Although the loop itself should be located within the toStringmethod of the DeckofCardsclass.
虽然循环本身应该位于类的toString方法中DeckofCards。
回答by TNT
Replace
代替
DeckofCards myDeck = new DeckofCards;
with
和
DeckofCards myDeck = new DeckofCards();
and myDeckwas never initialized to be an array.
并且myDeck从未被初始化为数组。
回答by Robert Moskal
In order to iterate through the DeckofCards you'll want to expose that private Card[] array. You can use the bean notation getCards() or just make the array public.
为了遍历 DeckofCards，您需要公开该私有 Card[] 数组。您可以使用 bean 符号 getCards() 或仅将数组设为公开。
public class DeckofCards {
private Card[] deck = new Card[52];
public DeckofCards(){
int i = 0;
for(int s = 1; s<5; s++){
for(int r = 1; r<14; r++){
deck[i].rank = r;
deck[i].suit = s;
i++;
}
}
}
public Card[] getCards(){
return deck;
}
}
I would probably just make the deck public.
我可能只是让甲板公开。
