blocks|key|1659765|text|int+*myArr[];|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1659766|这是错误的！你必须告诉编译器你的指针数组的大小。如果你声明为int+a[]会怎么样？您告诉编译器创建一个大小未知的整数数组，这在C%2B%2B中是不允许的。这就是为什么你不能这样做的原因。|unstyled|offset|length|style|CODE|1659767|我建议你这样做：|1659768|int+**myArr;

void+Matrix::initialize()
{
++++myArr+=+new+int*[myRows];+//note+int*+here!

++++for+(int+i=0;+i+<+myRows;+i%2B%2B)
++++{
++++++++myArr[i]+=+new+int[myColumns];
++++}
}|1659769|这现在应该可以用了。|1659770|entityMap^0|0|U|7|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|T|8|@$G|U|H|V|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$B|C]]|$1|O|3|P|5|F|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|F|7|Z|8|@]|9|@]|A|$]]]|R|$]]

<pre><code>int *myArr[];
</code></pre>

This is wrong! You've to tell the compiler the size also, of your array of pointer. How about if you declare <code>int a[]</code>. You're telling the compiler to create an array of int, of unknown size, which is not allowed in C++. That is why you cannot do that.

I would suggest you to do this:

<pre><code>int **myArr;

void Matrix::initialize()
{
 myArr = new int*[myRows]; //note int* here!

 for (int i=0; i &lt; myRows; i++)
 {
 myArr[i] = new int[myColumns];
 }
}
</code></pre>

This should work now.

blocks|key|1659786|text|您应该使用std::vector<>。它处理内存分配和释放的所有问题。而且它没有任何bug。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1659787|然后你专注于你的算法的真正目标。不在内存管理上:-)|1659788|typedef+std::vector<int>+Ints;
typedef+std::vector<Ints>+Matrix;
Matrix+myArray;|code-block|syntax|javascript|1659789|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You should use std::vector&lt;>. It deals with all the problems of memory allocation and deallocation.
And it does so without any bugs.

And then you focus yourself on the real goals of your algorithm. Not on memory management :-)

<pre><code>typedef std::vector&lt;int&gt; Ints;
typedef std::vector&lt;Ints&gt; Matrix;
Matrix myArray;
</code></pre>

blocks|key|2686689|text|尝试替换：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2686690|*myArr+=+new+int[myRows];|code-block|syntax|javascript|2686691|通过|2686692|myArr+=+new+int*[myRows];|2686693|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Try replacing:

<pre><code>*myArr = new int[myRows];
</code></pre>

by

<pre><code>myArr = new int*[myRows];
</code></pre>

blocks|key|4289432|text|我不确定你的项目是否需要你使用多级指针，如果没有，你可以用另一种方法来解决这个问题，就是把多维数组当作一个大平面数组。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4289433|这意味着当您到达一行的末尾时，后面的索引将是下一行的第一个元素。下面是代码可能的样子：|4289434|//+In+this+approach+the+double+pointer+int**
//+is+replaced+with+just+a+simple+int*
int+*myArr;

//+Here's+your+Matrix+ctor.+Note+the+use+of+the+initializer+list
Matrix::Matrix(int+n,+int+m)+:+myRows(n),+myColumns(m)
{
++++initialize();
}

void+Matrix::initialize()
{
++++myArr+=+new+int[myRows+*+myColumns];

++++/*+This+loop+is+no+longer+needed+since+we're+allocating+
+++++++one+big+chunk+at+once.
++++for+(int+i=0;+i+<+3;+i%2B%2B)//Only+set+to+3+since+myRows+is+acting+crazy
++++{
++++++myArr[i]+=+new+int[myColumns];
++++}
++++*/
}

//+To+retrieve+stuff+from+your+array
//+you+would+do+something+like+this:
int+Matrix::operator()+(const+int+x,+const+int+y)
{
++return+myArr[x+*+myRows+%2B+y];
}|code-block|syntax|javascript|4289435|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I'm not sure if you're project requires you to use multi-level pointers, if it doesn't another way you can approach this problem is to just treat the multi-dimensional array as one big flat array. 

That means when you reach the end of a row, the index after that would be the first element of the next row. Here's how the code might look:

<pre><code>// In this approach the double pointer int**
// is replaced with just a simple int*
int *myArr;

// Here's your Matrix ctor. Note the use of the initializer list
Matrix::Matrix(int n, int m) : myRows(n), myColumns(m)
{
 initialize();
}

void Matrix::initialize()
{
 myArr = new int[myRows * myColumns];

 /* This loop is no longer needed since we're allocating 
 one big chunk at once.
 for (int i=0; i &lt; 3; i++)//Only set to 3 since myRows is acting crazy
 {
 myArr[i] = new int[myColumns];
 }
 */
}

// To retrieve stuff from your array
// you would do something like this:
int Matrix::operator() (const int x, const int y)
{
 return myArr[x * myRows + y];
}
</code></pre>

Here we are once again good people of the internet.

This is the code I'm using:

<pre><code>//This is what is in the header file
int *myArr[]; // A two-dimensional array representing holding the matrix data

//This is what is in the definition file
Matrix::Matrix(int n, int m)
{
 myRows = n;
 myColumns = m;
 initialize();
}

void Matrix::initialize()
{
 *myArr = new int[myRows];

 for (int i=0; i &lt; 3; i++)//Only set to 3 since myRows is acting crazy
 {
 myArr[i] = new int[myColumns];
 }
}
</code></pre>

For some reason when I use myRows variable to create the myArr array it just seems to stop referencing the value it was pointing towards before. 

For instance I give it the value 3 and after the *myArr = new int[myRows] has been executed it changes the value of myRows to 9834496, which I don't understand. 

Does the "new" de-reference the variable or something? 
Or am I doing something wrong?

Oh and since this is a school practice project (so I won't blame you if you don't answer) I would prefer an answer over working code, so that I could know what I did wrong for future projects.

A variable seems to be de-referencing when I use it in a dynamic array (C++)

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在这里，我们又一次成为了互联网的好人。这是我使用的代码：//This is what is in the header fileint *myArr[]; // A two-dimensional array representing holding the matrix data//This is what is i...

问当我在动态数组(C++)中使用一个变量时，它似乎正在被解除引用
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问当我在动态数组(C++)中使用一个变量时，它似乎正在被解除引用EN