C++ 中是否存在 typename 关键字，以便向后兼容“C 模板”？
我正在上 C++ 课程，我的老师顺便提到 C++ 中存在 typename 关键字（而不是在模板声明中使用 class 关键字），例如向后兼容“C 模板”。
这让我大吃一惊。我从未在 ANSI C 中看到或听说过类似 C++ 模板的东西（也许除了预处理器……而且这根本不是同一件事）。那么，我是否错过了一些东西 >巨大的某处，或者这是gcc或其他东西的真正深奥的扩展，或者我的老师是不是离谱了？
I’m taking a C++ class, and my teacher mentioned in passing that the typename keyword existed in C++ (as opposed to using the class keyword in a template declaration), for backwards compatibility with “C templates.”
This blew my mind. I’ve never seen or heard tell of anything like C++’s templates (except, perhaps, the preprocessor… and that’s not really the same thing at all) in ANSI C. So, did I miss something huge somewhere, or is this a really esoteric extension by gcc or something, or is my teacher way off-base?
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我想说的是，C 确实没有原生模板，但是，您可以使其与某种 元编程，看看 web 你会发现如何...
另一件重要的事情是，C 是一种通用的编程语言，所以很多事情，比如面向对象、模板和其他一些事情都可以通过更多的努力来完成。
像 Gnome 这样的项目证明了它可以完成并且做得很好。
PS：抱歉我的英语很糟糕！
I wish to say that C really don't have a native template stuff, however, you can make it works fine with some kind of a MetaProgramming, take a look around the web you will find how to...
Another important thing to say is that C is a programming language to general purpose, so a lot of things like Object Orientation, template and some other things can be done with a little more effort.
Projects like Gnome are proof that it can be done and very well.
P.S.: Sorry about my terrible english!!!
我认为你的老师有失偏颇。
请参阅 Stan Lippman 的帖子：为什么 C++ 支持类型参数的类和类型名 这就是 C++ 支持两者的真正原因。
I think your teacher is off base.
See Stan Lippman's post: Why C++ Supports both Class and Typename for Type Parameters for the real reason why C++ supports both.
也许您老师的目标短语是“...为了与 C 类型向后兼容”，即认识到
template< 的问题。当会产生误导，就像其他人那样说。 但这不是一个类！:-)T是 C 风格的内置类型（例如char或int）时，class T>不久前，一些 GCC 人员建议 让模板机制可供 C 编译器使用将是实现 C99 的
Perhaps the phrase your teacher was aiming for was along the lines of "...for backwards compatibility with C types", i.e., recognizing the problem that
template<class T>is misleading whenTis a C-style built-in type such ascharorint, as others have said. But that's not a class! :-)A while back a few GCC folks were suggesting that making the template machinery available to the C compiler would be a good way to implement C99's
<tgmath.h>, but that doesn't appear to have come to anything.不，ANSI C 不支持模板。
http: //publib.boulder.ibm.com/infocenter/comphelp/v8v101/topic/com.ibm.xlcpp8a.doc/language/ref/keyword_typename.htm
No, ANSI C does not support templates.
http://publib.boulder.ibm.com/infocenter/comphelp/v8v101/topic/com.ibm.xlcpp8a.doc/language/ref/keyword_typename.htm
你的老师正在编造事情。 C 中不存在模板之类的东西。
typename关键字的存在有两个原因：说
template比说template< 更有意义;class T>因为T可以是非类类型，如int或double。它可用于解决
A::B * foo;等声明中的解析歧义。这是声明一个名为 foo 的变量，还是一个乘法表达式？ （答案：它被解析为后者。要使其成为声明，请编写typename A::B *foo;，它告诉编译器将A::B解释为类型名称，而不是变量名称。）请参阅 http://pages.cs.wisc。 edu/~driscoll/typename.html 了解详细说明。
Your teacher is making things up. There's no such thing as templates in C. The
typenamekeyword exists for two reasons:It makes more sense to say
template<typename T>thantemplate<class T>sinceTcan be non-class types likeintordouble.It can be used to resolve parsing ambiguities in declarations like
A::B * foo;. Does this declare a variable namedfoo, or is it a multiplication expression? (Answer: It's parsed as the latter. To make it a declaration writetypename A::B *foo;which tells the compiler to interpretA::Bas a type name, not a variable name.)See http://pages.cs.wisc.edu/~driscoll/typename.html for a detailed explanation.
不，不存在 C 模板之类的东西。
typename甚至不是 C 中的关键字。No, there's no such thing as a C template.
typenameisn't even a keyword in C.这似乎不对。 typename 在 C 中根本不是保留字。
也许他们说错/记错了，并想到了“C with Classes”。
This doesn't seem right. typename is not a reserved word at all in C.
Perhaps they misspoke/remembered and were thinking of "C with Classes".