blocks|key|394455|text|在c%2B%2B中，你可以这样做|type|unstyled|depth|inlineStyleRanges|entityRanges|data|394456|class+MyStruct
{
public:
++++MyStruct();

private:
++++unsigned+char+code;
++++unsigned+char+*data;
++++int+size;
};

MyStruct::MyStruct()+:
++++code(1)
++,+data(new+unsigned+char[3])
++,+size(3)
{
++++data[0]+=+1;
++++data[1]+=+2;
++++data[2]+=+3;
}+|code-block|syntax|javascript|394457|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In c++ you can just do it this way

<pre><code>class MyStruct
{
public:
 MyStruct();

private:
 unsigned char code;
 unsigned char *data;
 int size;
};

MyStruct::MyStruct() :
 code(1)
 , data(new unsigned char[3])
 , size(3)
{
 data[0] = 1;
 data[1] = 2;
 data[2] = 3;
} 
</code></pre>

blocks|key|795963|text|我假设你的问题只是关于C%2B%2B，而不是C，因为你是从你的基础结构派生出来的。我还将假定为C%2B%2B11。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|795964|为了获得您想要的内容，您可以使用以下语法：|795965|struct+MyStrusture1+:+MyStrusture
{
++++MyStrusture1()+:+MyStrusture({+1,+nullptr,+3+})+{}
};|code-block|syntax|javascript|795966|请注意，我初始化了指向nullptr的data指针以解释基本概念。|offset|length|style|CODE|795967|用你想要的方式用一些内容初始化它，现在这就比较棘手了。一种天真的方法是：|795968|struct+MyStrusture1+:+MyStrusture
{
++++MyStrusture1()+:+MyStrusture({+1,+new+unsigned+char[3]+{+1,+2,+3+},+3+})+{}
};|795969|但这会产生各种各样的问题，例如谁应该删除data以及何时删除。我的猜测是，你根本不想要动态分配，而基结构中的指针实际上应该是一个数组：|795970|struct+MyStrusture{
++++unsigned+char+code;
++++unsigned+char+data[3];
++++int+size;
};

struct+MyStrusture1+:+MyStrusture
{
++++MyStrusture1()+:+MyStrusture({+1,+{+1,+2,+3+},+3+})+{}
};|795971|如果大小是可变的，可以使用std::vector：|795972|#include+<vector>

struct+MyStrusture{
++++unsigned+char+code;
++++std::vector<unsigned+char>+data;
++++int+size;
};

struct+MyStrusture1+:+MyStrusture
{
++++MyStrusture1()+:+MyStrusture({+1,+{+1,+2,+3+},+3+})+{}
};|795973|entityMap^0|0|0|0|B|7|J|4|0|0|0|K|4|0|0|D|B|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|15|8|@$K|16|L|17|M|N]|$K|18|L|19|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Q|3|R|5|F|7|1B|8|@]|9|@]|A|$G|H]]|$1|S|3|T|5|6|7|1C|8|@$K|1D|L|1E|M|N]]|9|@]|A|$]]|$1|U|3|V|5|F|7|1F|8|@]|9|@]|A|$G|H]]|$1|W|3|X|5|6|7|1G|8|@$K|1H|L|1I|M|N]]|9|@]|A|$]]|$1|Y|3|Z|5|F|7|1J|8|@]|9|@]|A|$G|H]]|$1|10|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|11|$]]

I assume your question is only about C++, not C, because you derive from your base structure. I'll also assume C++11.

In order to get what you want, you can use the following syntax:

<pre><code>struct MyStrusture1 : MyStrusture
{
 MyStrusture1() : MyStrusture({ 1, nullptr, 3 }) {}
};
</code></pre>

Note that I initialized your <code>data</code> pointer to <code>nullptr</code> to explain the base concept.

Initializing it with some contents the way you want to, now that's trickier. A naive approach would be:

<pre><code>struct MyStrusture1 : MyStrusture
{
 MyStrusture1() : MyStrusture({ 1, new unsigned char[3] { 1, 2, 3 }, 3 }) {}
};
</code></pre>

But this creates all kinds of problems, for example who is supposed to delete <code>data</code> and when. My guess is that you don't want dynamic allocation at all, and the pointer in your base structure should actually be an array:

<pre><code>struct MyStrusture{
 unsigned char code;
 unsigned char data[3];
 int size;
};

struct MyStrusture1 : MyStrusture
{
 MyStrusture1() : MyStrusture({ 1, { 1, 2, 3 }, 3 }) {}
};
</code></pre>

If the size should be variable, <code>std::vector</code> can be used:

<pre><code>#include &lt;vector&gt;

struct MyStrusture{
 unsigned char code;
 std::vector&lt;unsigned char&gt; data;
 int size;
};

struct MyStrusture1 : MyStrusture
{
 MyStrusture1() : MyStrusture({ 1, { 1, 2, 3 }, 3 }) {}
};
</code></pre>

blocks|key|394514|text|是的，您可以使用构造函数来完成此操作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|394515|struct+MyStrusture{
++++unsigned+char+code;
++++unsigned+char+*+data;
++++int+size;
};

struct+MyStrusture1+:+MyStrusture{
++++MyStrusture1();+//+the+constructor
};|code-block|syntax|javascript|394516|然后在.cpp文件中定义MyStrusture1()构造函数，并在其中初始化数据成员：|offset|length|style|CODE|394517|MyStrusture1::MyStrusture1()
:+++MyStrusture+{+1,+new+unsigned+char[3]+{+1,+2,+3+},+3+}
{
}|394518|entityMap^0|0|0|C|E|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]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Yes, you can do it using a constructor:

<pre><code>struct MyStrusture{
 unsigned char code;
 unsigned char * data;
 int size;
};

struct MyStrusture1 : MyStrusture{
 MyStrusture1(); // the constructor
};
</code></pre>

Then define the <code>MyStrusture1()</code> constructor in a .cpp file, and initialize the data members there:

<pre><code>MyStrusture1::MyStrusture1()
: MyStrusture { 1, new unsigned char[3] { 1, 2, 3 }, 3 }
{
}
</code></pre>

Suppose we have the following structure defined:

<pre><code>struct MyStrusture{
 unsigned char code;
 unsigned char * data;
 int size;
};
</code></pre>

Is that possible to define a new struct which inherits from MyStructure and set its members at the same time? Something like this:

<pre><code>struct MyStrusture1 : MyStrusture{
 code=1;
 data={1,2,3};
 size=3;
 };
</code></pre>

I have tried it but it does not get compiled I have to redefine each member in child structure. How could I reach parent members in the derived structure??

By the way, My opinion is to use MyStrusture as a function parameter so I could write the signature in this form <code>method1(MyStructure)</code> when I call the function I can use MyStructure1 or 2 or etc. Is this a standard way or I should use another technique?

Thanks for any help.

Is it possible to define a child from a struct and set it members?

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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假设我们定义了以下结构：struct MyStrusture{    unsigned char code;    unsigned char * data;    int size;};可以定义一个从MyStructure继承的新结构，同时设置它的成员吗？如下所示：struct MyStrusture1 : MySt...

问是否可以从结构定义一个子级并将其设置为成员？
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问是否可以从结构定义一个子级并将其设置为成员？EN