我使用。h，因为这是微软使用的，也是他们的代码生成器创建的。没必要违背常理。

c++ ("C Plus Plus")作为.cpp是有意义的

扩展名为.hpp的头文件没有相同的逻辑流。

Bjarne Stroustrup和Herb Sutter在他们的c++核心指南(https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#S-source)中对这个问题有一个声明，该指南也提到了标准扩展(c++ 11, c++ 14等)的最新变化。

SF.1: Use a .cpp suffix for code files and .h for interface files if your Y project doesn't already follow another convention Reason It's a longstanding convention. But consistency is more important, so if your project uses something else, follow that. Note This convention reflects a common use pattern: Headers are more often shared with C to compile as both C++ and C, which typically uses .h, and it's easier to name all headers .h instead of having different extensions for just those headers that are intended to be shared with C. On the other hand, implementation files are rarely shared with C and so should typically be distinguished from .c files, so it's normally best to name all C++ implementation files something else (such as .cpp). The specific names .h and .cpp are not required (just recommended as a default) and other names are in widespread use. Examples are .hh, .C, and .cxx. Use such names equivalently. In this document, we refer to .h and .cpp > as a shorthand for header and implementation files, even though the actual extension may be different. Your IDE (if you use one) may have strong opinions about suffices.

我不是这种惯例的大粉丝，因为如果你正在使用像boost这样的流行库，你的一致性已经被打破了，你最好使用.hpp。

编辑[增加了Dan Nissenbaum的建议]:

根据约定，当原型在头文件中定义时，使用.hpp文件。对于模板，头文件中的这种定义很有用，因为编译器只在模板实例化时为每种类型生成代码。因此，如果它们没有在头文件中定义，它们的定义将不会在链接时从其他编译单元解析。如果你的项目只使用c++，并且大量使用模板，这个约定将会很有用。

某些遵循此约定的模板库提供带有.hpp扩展名的头文件，以表明它们没有相应的.cpp文件。

另一个习惯是用.h表示C头文件，用.hpp表示c++头文件;boost库就是一个很好的例子。

引用自Boost FAQ， 文件扩展名向人类传递文件的“类型” 还有计算机程序。'.h'扩展名用于C头文件 文件，因此传达了关于c++头文件的错误信息 文件。不使用扩展不能传达任何信息，还会迫使检查 确定文件内容的类型。明确使用“。hpp” 将其标识为c++头文件，并且在实际应用中工作良好。 (Rainer Deyke)

我一直认为.hpp头文件是.h和.cpp文件的混合…还包含实现细节的标头。

通常，当我看到(并使用).hpp作为扩展名时，没有相应的.cpp文件。正如其他人所说，这不是一个严格的规则，只是我倾向于使用.hpp文件。

There is no advantage to any particular extension, other than that one may have a different meaning to you, the compiler, and/or your tools. header.h is a valid header. header.hpp is a valid header. header.hh is a valid header. header.hx is a valid header. h.header is a valid header. this.is.not.a.valid.header is a valid header in denial. ihjkflajfajfklaf is a valid header. As long as the name can be parsed properly by the compiler, and the file system supports it, it's a valid header, and the only advantage to its extension is what one reads into it.

话虽如此，能够基于扩展准确地做出假设是非常有用的，因此对于头文件使用一组易于理解的规则将是明智的。就我个人而言，我更喜欢这样做:

If there are already any established guidelines, follow them to prevent confusion. If all source files in the project are for the same language, use .h. There's no ambiguity. If some headers are compatible with multiple languages, while others are only compatible with a single language, extensions are based on the most restrictive language that a header is compatible with. A header compatible with C, or with both C & C++, gets .h, while a header compatible with C++ but not C gets .hpp or .hh or something of the sort.

This, of course, is but one of many ways to handle extensions, and you can't necessarily trust your first impression even if things seem straightforward. For example, I've seen mention of using .h for normal headers, and .tpp for headers that only contain definitions for templated class member functions, with .h files that define templated classes including the .tpp files that define their member functions (instead of the .h header directly containing both the function declaration and the definition). For another example, a good many people always reflect the header's language in its extension, even when there's no chance of ambiguity; to them, .h is always a C header and .hpp (or .hh, or .hxx, etc.) is always a C++ header. And yet again, some people use .h for "header associated with a source file" and .hpp for "header with all functions defined inline".

考虑到这一点，主要的优势在于始终以相同的风格命名你的头文件，并使这种风格对任何检查你的代码的人来说都很明显。这样，任何熟悉您通常的编码风格的人都可以粗略地看一下，就可以确定您对任何给定扩展的意思。