what's C++'s "typename"

[gsirk]

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could someone pls give me a simple example of typename? how to use it?

[softtouch]

C++ use the keyword typename if you have a qualified name that refers to a type and depends on a template parameter. Only use the keyword typename in template declarations and definitions.
The following example illustrates the use of the keyword typename:

template<class T> class A
{
 T::x(y);
 typedef char C;
 A::C d;
}

The statement

T::x(y)

is ambiguous. It could be a call to function x() with a nonlocal argument y, or it could be a declaration of variable y with

type T::x

. C++ will interpret this statement as a function call. In order for the compiler to interpret this statement as a declaration, you would add the keyword typename to the beginning of it. The statement

A::C d;

is ill-formed. The class A also refers to A<T> and thus depends on a template parameter.
You must add the keyword typename to the beginning of this declaration:

typename A::C d;

You can also use the keyword typename in place of the keyword class in template parameter declarations.

[TatS™]

murag sa akong nabasahan no , kay mo define kag name para reusable imong code..

ex.

typedef length= 69 ;

in your entire code imong gamiton is length na keyword so in case mausab ang value ni length, dili naka mag ukay-ukay sa imng code aron mag usab ni length, anha nalang ka sa imong declaration silbi..

mao siguro na
hehe

[bisdakgyud]

dili man siguro typedef angay gamiton sa above example kun dili #define. typename could be about the different data type in C++/C like int,float,char?

[softtouch]

I gave the explanation above, this is the correct definition of typename.