Difference of keywords 'typename' and 'class' in templates?
对于模板，我看到了两个声明：
1 2 | template < typename T > template < class T > |
有什么区别？
在下面的例子中，这些关键词究竟意味着什么(摘自德国维基百科关于模板的文章)？
1 2 3 4 5 | template < template < typename, typename > class Container, typename Type > class Example { Container< Type, std::allocator < Type > > baz; }; |
(P)EDOCX1和EDOCX1的英文本2是互通的，基本上是一个具体的例子：(p)字母名称(P)and(p)字母名称(P)是相等的。(p)(P)Having said that，there are specific cases where there is a difference between EDOCX1 penal 1 and EDOCX1 penal 2.(p)(P)The first one is in the case of dependent types.EDOCX1 is used to declaration when you are referenceing a nested type that depends on another template parameter，such as the EDOCX1 big 10 in this example：(p)字母名称(P)The second one you actually show in your question，though you might not realize it：(p)字母名称(P)当具体说明一个Template Template，the EDOCX1 plography 2 must be used as above-it is not interchangeable with EDOCX1 indicational 1 in this case(note:since C++17 both keywords are allowed in this case).(p)(P)你也必须使用EDOCX1(音译2)当明确的瞬间(p)字母名称(P)I'm sure that there are other cases that I've missed，but the bottom line is：these two keywords are not equivalent，and these are some common cases where you need to use one or the other.(p)
(P)For naming template parameters，EDOCX1 universal 1 and EDOCX1.14.1.2§14.1.2：(p)布尔奇1(P)EDOCX1 sinc 1.However is possible in another context when using templates-to hint at the compiler that you are referring to a dependent type.14.6.2§14.6.2：(p)布尔奇1(P)例如：(p)字母名称(P)Without EDOCX1 inal.The compiler can't tell in general whether you are referring to a type or not.(p)
(P)在没有技术区别的情况下，我发现有两种不同的说法。(p)(P)For a template that should accept any type as t，including built-ins(such as an array)(p)字母名称(P)For a temple that will only work where it is a real class.(p)字母名称(P)但是，请记住，这是一个清除一些人使用。Not mandated by the standard or enforced by compilers(p)
(P)这一PIECE of snippet is from C++First book.我知道这是错的。(p)(P)Each type parameter must be before the keyword class or typename:(p)字母名称(P)这些Keywords have the same meaning and can be used interchangeably inside a temple parameter list.a Template parameter list can use both keywords：(p)字母名称(P)It may seem more intuitive to use the keyword typename rather than class to designate a temple type parameter.在所有情况下，我们可以使用购买-in(Nonclass)类型作为一个Template type argument。Moreover，type name more clearly indicates that the name that follows is a type name.然而，typename was added to C++after templates were already in widespread use；some programmers continue to use class exclusively(p)