blocks|key|735340|text|为什么不简单地|type|unstyled|depth|inlineStyleRanges|entityRanges|data|735341|public+Date(){
++++data+=+new+int[]{0,0,0};
}|code-block|syntax|javascript|735342|出现错误的原因是因为int[]+data+=+...声明了一个新变量并隐藏了字段data|offset|length|style|CODE|735343|但是，需要注意的是，数组的内容已经初始化为0(int的默认值)|735344|entityMap^0|0|0|A|G|14|4|0|N|3|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@$I|Y|J|Z|K|L]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|P|$]]

why not simply 

<pre><code>public Date(){
 data = new int[]{0,0,0};
}
</code></pre>

the reason you got the error is because <code>int[] data = ...</code> declares a new variable and hides the field <code>data</code>

however it should be noted that the contents of the array are already initialized to 0 (the default value of <code>int</code>)

blocks|key|735427|text|在您的构造函数中，您将创建另一个int数组：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|735428|+public+Date(){
++int[]+data+=+{0,0,0};
++}|code-block|syntax|javascript|735429|试试这个：|735430|+data+=+{0,0,0};|735431|注意:顺便说一下，如果数组元素被声明为实例变量，则不需要对其进行初始化。实例变量自动获取其默认值，对于整数数组，默认值为全零。|735432|如果您有本地声明的数组，则需要初始化每个元素。|735433|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

in your constructor you are creating another int array:

<pre><code> public Date(){
 int[] data = {0,0,0};
 }
</code></pre>

Try this:

<pre><code> data = {0,0,0};
</code></pre>

NOTE: By the way you do NOT need to initialize your array elements if it is declared as an instance variable. Instance variables automatically get their default values, which for an integer array, the default values are all zeroes.

If you had locally declared array though they you would need to initialize each element.

blocks|key|735528|text|最好的方法是不编写任何初始化语句。这是因为如果你编写int+a[]=new+int[3]，那么默认情况下，在Java语言中，数组的所有值，即a[0]、a[1]和a[2]都被初始化为0！关于隐藏字段的局部变量，请将您的整个代码张贴出来，以便我们得出结论。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|735529|entityMap^0|Q|I|1Y|4|23|4|28|4|2I|1|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]|$9|O|A|P|B|C]|$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|G|$]]

The best way is not to write any initializing statements. This is because if you write 
<code>int a[]=new int[3]</code> then by default, in Java all the values of array i.e. <code>a[0]</code>, <code>a[1]</code> and <code>a[2]</code> are initialized to <code>0</code>! Regarding the local variable hiding a field, post your entire code for us to come to conclusion.

blocks|key|735577|text|private+int[]+data+=+new+int[3];|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|735578|这已经将数组元素初始化为0。你不需要在构造函数中重复这一点。|unstyled|735579|在你的构造函数中，它应该是：|735580|data+=+new+int[]{0,+0,+0};|735581|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$B|C]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>private int[] data = new int[3];
</code></pre>

This already initializes your array elements to 0. You don't need to repeat that again in the constructor.

In your constructor it should be:

<pre><code>data = new int[]{0, 0, 0};
</code></pre>

blocks|key|519198|text|你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|519199|public+class+Data+{
++++private+int[]+data;

++++public+Data()+{
++++++++data+=+new+int[]{0,+0,+0};
++++}
}|code-block|syntax|javascript|519200|它在构造函数中初始化data，或者：|offset|length|style|CODE|519201|public+class+Data+{
++++private+int[]+data+=+new+int[]{0,+0,+0};

++++public+Data()+{
++++++++//+data+already+initialised
++++}
}|519202|它在执行构造函数中的代码之前初始化data。|519203|entityMap^0|0|0|A|4|0|0|H|4|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

You could either do:

<pre><code>public class Data {
 private int[] data;

 public Data() {
 data = new int[]{0, 0, 0};
 }
}
</code></pre>

Which initializes <code>data</code> in the constructor, or:

<pre><code>public class Data {
 private int[] data = new int[]{0, 0, 0};

 public Data() {
 // data already initialised
 }
}
</code></pre>

Which initializes <code>data</code> before the code in the constructor is executed.

blocks|key|735718|text|这是因为，在构造函数中，您声明了一个与属性同名的局部变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|735719|要分配一个所有元素都初始化为零的整数数组，请在构造函数中写入以下内容：|735720|data+=+new+int[3];|code-block|syntax|javascript|735721|要分配具有其他初始值的整数数组，请将以下代码放入构造函数中：|735722|int[]+temp+=+{2,+3,+7};
data+=+temp;|735723|或者：|735724|data+=+new+int[]+{2,+3,+7};|735725|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

This is because, in the constructor, you declared a local variable with the same name as an attribute. 

To allocate an integer array which all elements are initialized to zero, write this in the constructor:

<pre><code>data = new int[3];
</code></pre>

To allocate an integer array which has other initial values, put this code in the constructor: 

<pre><code>int[] temp = {2, 3, 7};
data = temp;
</code></pre>

or:

<pre><code>data = new int[] {2, 3, 7};
</code></pre>

I have a class and in that class I have this:

<pre><code> //some code
 private int[] data = new int[3];
 //some code
</code></pre>

Then in my constructor:

<pre><code>public Date(){
 data[0] = 0;
 data[1] = 0;
 data[2] = 0;
}
</code></pre>

If I do this, everything is OK. Default data values are initialized but if I instead do this:

<pre><code>public Date(){
 int[] data = {0,0,0};
}
</code></pre>

It says:

<pre><code>Local variable hides a field
</code></pre>

Why?

What's the best way to initialize an array inside the constructor?

Java Initialize an int array in a constructor

我有一个班级，在那个班级里我有这个： //some code private int[] data = new int[3]; //some code然后在我的构造函数中：public Date(){    data[0] = 0;    data[1] = 0;    data[2] = 0;}如果我这样做，一切都会...

问Java在构造函数中初始化整型数组
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Java在构造函数中初始化整型数组EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Java在构造函数中初始化整型数组
EN