Re: How can I do a template function that returns vector of template type?

From:
"kepeng@gmail.com" <kepeng@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Sat, 12 Apr 2008 12:50:06 -0700 (PDT)
Message-ID:
<99696cd2-347e-47e8-a360-8d9dcad07dbb@b5g2000pri.googlegroups.com>
On 4=D4 12=C8=D5, =CF =CE=E711=CA=B152=B7=D6, Rob <someidunknown1...@yah=
oo.com> wrote:

On Apr 12, 9:24 am, Davis King <davis...@gmail.com> wrote:

On Apr 11, 10:46 pm, Ian Collins <ian-n...@hotmail.com> wrote:

Rob wrote:

I tried that and it still does not compile. I think it's because the=

overloaded methods that will be created for the templated function
only differ by return type and not by args (the args are always the
same). Am I correct in that overloaded methods must differ in args?


Yes.

--
Ian Collins.


Uh, I beg to differ. I have used similar templated functions
frequently with no trouble. Think about boost::lexical_cast for
example. That works just fine even if you try to cast a string to an
int and also a string to a double. But by the logic of this thread
that should be illegal because the overloaded methods created by the
template wouldn't differ in their arguments.

I also just compiled this program in gcc and it worked fine for me.

#include <vector>
#include <string>

using namespace std;

template <typename T>
vector<T> get(int c)
{
    return vector<T>();

}

int main()
{
    vector<vector<string> > ret1 = get<vector<string> >( 0 );
    vector<string> ret2 = get<string >( 0 );

}

What exactly are you trying to compile that isn't working?

-Davis


You're a genius!! The problem was in what I was specializing to. I'd
accidentally done:

     vector<vector<string> > ret = get<vector<string> >( c );

when it should have been:

     vector<vector<string> > ret = get<string>( c );


Is this you want?

template <typename MyType>
std::vector<std::vector<MYType> > get(SomeClass c)
{
     ...elided...
}

int main()
{
    std::vector<std::vector<std::string> ret = get<std::string>( c );
}

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