<s>
"	O
typename	B-Language
"	O
is	O
a	O
keyword	O
in	O
the	O
C++	B-Language
programming	I-Language
language	I-Language
used	O
when	O
writing	O
templates	B-Application
.	O
</s>
<s>
It	O
is	O
used	O
for	O
specifying	O
that	O
a	O
dependent	O
name	O
in	O
a	O
template	B-Application
definition	O
or	O
declaration	O
is	O
a	O
type	O
.	O
</s>
<s>
In	O
the	O
original	O
C++	B-Language
compilers	O
before	O
the	O
first	O
ISO	O
standard	O
was	O
completed	O
,	O
the	O
typename	B-Language
keyword	O
was	O
not	O
part	O
of	O
the	O
C++	B-Language
language	I-Language
and	O
Bjarne	O
Stroustrup	O
used	O
the	O
class	O
keyword	O
for	O
template	B-Application
arguments	O
instead	O
.	O
</s>
<s>
While	O
typename	B-Language
is	O
now	O
the	O
preferred	O
keyword	O
,	O
older	O
source	O
code	O
may	O
still	O
use	O
the	O
class	O
keyword	O
instead	O
(	O
for	O
example	O
see	O
the	O
difference	O
in	O
source	O
code	O
examples	O
between	O
The	O
Design	O
and	O
Evolution	O
of	O
C++	B-Language
by	O
Bjarne	O
Stroustrup	O
published	O
in	O
1994	O
and	O
the	O
source	O
code	O
examples	O
in	O
The	O
C++	B-Language
Programming	I-Language
Language	I-Language
:	O
Fourth	O
Edition	O
by	O
Bjarne	O
Stroustrup	O
published	O
in	O
2013	O
)	O
.	O
</s>
<s>
In	O
C++'s	O
generic	B-Language
programming	I-Language
feature	O
known	O
as	O
"	O
templates	B-Application
"	O
,	O
typename	B-Language
can	O
be	O
used	O
for	O
introducing	O
a	O
template	B-Application
parameter	O
:	O
</s>
<s>
The	O
reason	O
it	O
does	O
n't	O
know	O
is	O
that	O
T::bar	O
is	O
a	O
"	O
template-parameter	O
dependent	O
name	O
"	O
,	O
or	O
"	O
dependent	O
name	O
"	O
for	O
short	O
,	O
which	O
then	O
could	O
represent	O
anything	O
named	O
"	O
bar	O
"	O
inside	O
a	O
type	O
passed	O
to	O
foo( )	O
,	O
which	O
could	O
include	O
typedefs	B-Language
,	O
enums	B-Language
,	O
variables	O
,	O
etc	O
.	O
</s>
<s>
To	O
resolve	O
this	O
ambiguity	O
,	O
the	O
C++	B-Language
Language	I-Language
Standard	O
declares	O
:	O
</s>
<s>
A	O
name	O
used	O
in	O
a	O
template	B-Application
declaration	O
or	O
definition	O
and	O
that	O
is	O
dependent	O
on	O
a	O
template-parameter	O
is	O
assumed	O
not	O
to	O
name	O
a	O
type	O
unless	O
the	O
applicable	O
name	O
lookup	O
finds	O
a	O
type	B-Language
name	I-Language
or	O
the	O
name	O
is	O
qualified	O
by	O
the	O
keyword	O
typename	B-Language
.	O
</s>
<s>
For	O
this	O
,	O
the	O
typename	B-Language
keyword	O
is	O
used	O
:	O
</s>
