在c++中思考时遇到的友元迭代器和友元类迭代器有什么区别？
《Thinking in C++》第 1 卷第 16 章：模板简介。 背景：
请注意，不要只是说：
friend iterator; // Make it a friend
这段代码有：
friend class iterator; // Make it a friend
这很重要，因为名称“iterator”已经在包含文件的范围内。
埃克尔上面的真正意思是什么？ 看来 friend iterator 编译正确，我看不到差异。谁能告诉答案吗？谢谢
In Thinking in C++ Volume 1, chapter 16: Introduction to Templates.
The context:
Notice that instead of just saying:
friend iterator; // Make it a friend
This code has:
friend class iterator; // Make it a friend
This is important because the name "iterator" is already in scope, from an included file.
What does Eckel really mean above?
It seems friend iterator compiles correctly and I can't see the differences. Can anyone tell the answer? Thanks
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根据 C++03 标准第 11.4 节：
应在类的友元声明中使用详细类型说明符。
因此，根据规范，编译器将发出警告您认为迭代器的友元声明必须是详细的类名。如果不是，那么编译者在这个特定方面不符合标准。
什么是详细类型说明符？
C++ 使用详细的类型说明符来明确告诉编译器将类视为类。我认为 MSDN 可以比我更好地解释它，所以检查 this 以获得详细解释。
As per C++03 standard section 11.4:
An elaborated-type-specifier shall be used in a friend declaration for a class.
So as per the specification the compiler will warn you that the friend declaration of
iteratormust be an elaborated class name. If not then the complier is non-compliant to the standard in this particular aspect.What are Elaborated Type Specifiers?
C++ use elaborated type specifiers to tell the compiler explicitly to treat a class as a class. I think MSDN can explain it much better than I can, So check this out for detailed explanation.