blocks|key|5537690|text|您可以做的是在头部中声明字符串，并在.cpp中对其进行初始化。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5537691|在MyClass.h中|5537692|#include+<string>
class+MyClass
{
++static+std::string+foo;
}|code-block|syntax|javascript|5537693|在MyClass.cpp中|5537694|#include+"MyClass.h"
std::string+MyClass::foo+=+"bar"|5537695|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

What you can do is declare the string in the header and initialize it in your .cpp.

in MyClass.h

<pre><code>#include &lt;string&gt;
class MyClass
{
 static std::string foo;
}
</code></pre>

in MyClass.cpp

<pre><code>#include "MyClass.h"
std::string MyClass::foo = "bar"
</code></pre>

blocks|key|5537713|text|将声明与定义分开。在头文件中，执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5537714|static+string+description;|code-block|syntax|javascript|5537715|然后在恰好一个翻译单元(一个CPP文件)中，执行以下操作：|5537716|string+type::description+=+"foo";|5537717|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|$]]

Seperate the declaration from the definition. In the header file, do this:

<pre><code>static string description;
</code></pre>

And then in exactly one translation unit (one CPP file), do this:

<pre><code>string type::description = "foo";
</code></pre>

blocks|key|3809520|text|忽略具体的错误消息，核心问题是您试图在声明中初始化静态成员属性，而通常应该在定义中完成此操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3809521|//+header
struct+test+{
++static+std::string+x;
};
//+single+cpp
std::string+test::x+=+"foo";|code-block|syntax|javascript|3809522|现在回到错误消息。C%2B%2B03标准中有一个例外，它允许为常量整数类型的声明提供初始值设定项，以便该值在包括标头的所有转换单元中都可见，从而可以用作常量表达式：|3809523|//+header
struct+test+{
+++static+const+int+size+=+10;
};
//+some+translation+unit+can+do
struct+A+{
+++int+array[test::size];
};|3809524|如果该值是在变量的定义中定义的，则编译器只能在该单个翻译单元中使用它。看起来你的编译器正在做两个测试，一个是常量测试，另一个是整体测试，因此有两个错误消息。|3809525|另一件可能影响编译器中的设计的事情是，C%2B%2B11标准允许在类的非静态成员的声明中使用初始化器，然后这些初始化器将在每个没有为该字段提供值的构造函数的初始化器列表中使用：|3809526|struct+test+{
+++int+a+=+10;
+++int+b+=+5;
+++test()+:+a(5)+//+b(5)+implicitly+generated
+++{}+
};|3809527|这与您的特定问题无关，因为您的成员是静态的，但这可能解释了为什么编译器中的测试按原样拆分。|3809528|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

Ignoring the specific error message the core issue is that you are trying to initialize a static member attribute in the declaration while in general that should be done in the definition.

<pre><code>// header
struct test {
 static std::string x;
};
// single cpp
std::string test::x = "foo";
</code></pre>

Now back to the error messages. There is an exception in the C++03 standard that allows to provide an initializer to the declaration of a constant integral type, so that the value can be visible in all translation units that include the header and can thus be used as a constant expression:

<pre><code>// header
struct test {
 static const int size = 10;
};
// some translation unit can do
struct A {
 int array[test::size];
};
</code></pre>

If the value was defined in the definition of the variable, then the compiler could only use it in that single translation unit. It seems that your compiler is doing two tests, one for const-ness and a separate one for the integral part and thus two error messages.

Another thing that might affected that design in the compiler is that the C++11 standard allows for initializers in the declaration of non-static members of a class, which will then be used in the initializer list of each constructor that does not provide a value for that field:

<pre><code>struct test {
 int a = 10;
 int b = 5;
 test() : a(5) // b(5) implicitly generated
 {} 
};
</code></pre>

This is unrelated to your particular issue, as your member is static but it probably explains why the tests in the compiler were split as they are.

blocks|key|5537790|text|我不知道在静态成员和常量成员之间到底需要什么。静态成员将与类本身相关联，而不是与实例相关联；常量成员是与实例相关联的，并且将是常量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5537791|但是，这可能是this的副本|offset|length|5537792|问候|5537793|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/5019856/c-initialize-static-variables-in-class^0|0|7|4|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@$D|R|E|S|1|T]]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

I don't know what exactly you need between a static member and a constant member. A static member will be associated with the class itself and not with the instances, and a constant member is a associated with the instance and will be constant.

However, this is a possible duplicate of <a href="https://stackoverflow.com/questions/5019856/c-initialize-static-variables-in-class">this</a>

Regards

I am trying to create a static string in my class: (in my header file)

<pre><code>static string description = "foo";
</code></pre>

but I'm getting this error:

<pre><code>IntelliSense: a member with an in-class initializer must be const
</code></pre>

if I change it to this:

<pre><code>static const string description = "foo";
</code></pre>

I get this error instead:

<pre><code>IntelliSense: a member of type "const std::string" cannot have an in-class initializer
</code></pre>

What did I do wrong?

C++ a member with an in-class initializer must be const

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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我正在尝试在我的类中创建一个静态字符串：(在我的头文件中)static string description = "foo";但是我得到了这个错误：IntelliSense: a member with an in-class initializer must be const如果我把它改成这样：static cons...

问具有类内初始值设定项的C++成员必须为常量
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问具有类内初始值设定项的C++成员必须为常量EN