| Topic: |
DEVELOP > c-Plus-Plus |
| User: |
"Chris" |
| Date: |
25 Jan 2008 04:33:38 PM |
| Object: |
Newbie question about templates |
Hi,
It have a simple question about templates. I am using the OpenWatcom
compiler. Here is some test code
#include <vector>
using namespace std;
int testInt(vector<int>& x1)
{
return x1[0];
};
template<typename T>
T testTemplate(vector<T>& x1)
{
T y = x1[0];
return y;
};
The compiler complains about the function "testTemplate": non-type
parameter supplied for a type argument.
I am not seeing the problem. I appreciate any help in this matter.
Thanks
Chris
.
|
|
| User: "Pascal Bourguignon" |
|
| Title: Re: Newbie question about templates |
25 Jan 2008 05:26:03 PM |
|
|
Chris <cnathaide@yahoo.com> writes:
Hi,
It have a simple question about templates. I am using the OpenWatcom
compiler. Here is some test code
#include <vector>
using namespace std;
int testInt(vector<int>& x1)
{
return x1[0];
};
template<typename T>
T testTemplate(vector<T>& x1)
{
T y = x1[0];
return y;
};
The compiler complains about the function "testTemplate": non-type
parameter supplied for a type argument.
I am not seeing the problem. I appreciate any help in this matter.
Neither do we.
-*- mode: compilation; default-directory: "/tmp/" -*-
Compilation started at Sat Jan 26 00:25:24
cat a.c++ ; g++ -c -o a.o a.c++
#include <vector>
using namespace std;
int testInt(vector<int>& x1)
{
return x1[0];
};
template<typename T>
T testTemplate(vector<T>& x1)
{
T y = x1[0];
return y;
};
Compilation finished at Sat Jan 26 00:25:25
Perhaps you could try to provide us with the true program that gives
you errors, and avoid having us try to guess?
--
__Pascal Bourguignon__ http://www.informatimago.com/
Grace personified,
I leap into the window.
I meant to do that.
.
|
|
|
|
| User: "Salt_Peter" |
|
| Title: Re: Newbie question about templates |
25 Jan 2008 07:13:56 PM |
|
|
On Jan 25, 5:33 pm, Chris <cnatha...@yahoo.com> wrote:
Hi,
It have a simple question about templates. I am using the OpenWatcom
compiler. Here is some test code
#include <vector>
using namespace std;
int testInt(vector<int>& x1)
{
return x1[0];
};
extraneous semicolon, the above is a function definition
template<typename T>
T testTemplate(vector<T>& x1)
{
T y = x1[0];
return y;
return x1[0];
};
no semicolon
The compiler complains about the function "testTemplate": non-type
parameter supplied for a type argument.
I am not seeing the problem. I appreciate any help in this matter.
Thanks
Chris
Templated functions don't exist until a version of the template is
instantiated or generated.
So until you supply how you are using the above template, we can't
really offer much help.
This works:
int main()
{
std::vector<int> v(10, 9);
std::cout << testTemplate(v) << std::endl;
}
/*
9
*/
.
|
|
|
| User: "Chris" |
|
| Title: Re: Newbie question about templates |
25 Jan 2008 09:24:32 PM |
|
|
Thanks for your replies. Here is my complete code.
#include <vector>
#include <iostream.h>
using namespace std;
template<typename T>
T testTemplate(vector<T>& x1)
{
return x1[0];
}
int main()
{
vector<int> v(10,9);
std::cout << testTemplate(v) << std::endl;
}
The compiler shows the following output:
CL /nologo /G5 /MDd /W4 /GX /Od /FD /D "WIN32" /D "_DEBUG" /D
"_WINDOWS" /D "_MBCS" /c ..\test.cpp
C:\WATCOM\H\vector(50): Error! E350: col(51) non-type parameter
supplied for a type argument
C:\WATCOM\H\vector(50): Note! N393: col(51) included from ..
\test.cpp(1)
...\test.cpp(15): Error! E651: col(34) cannot instantiate testTemplate
...\test.cpp(6): Note! N649: col(3) template function '?
testTemplate( std::vector<?,<error>> & )' defined in: ..\test.cpp(6)
(col 3)
Thanks for your help.
Chris
.
|
|
|
| User: "Salt_Peter" |
|
| Title: Re: Newbie question about templates |
25 Jan 2008 09:41:09 PM |
|
|
On Jan 25, 10:24 pm, Chris <cnatha...@yahoo.com> wrote:
Thanks for your replies. Here is my complete code.
#include <vector>
#include <iostream.h>
#include <iostream>
using namespace std;
instead of using namespace...
template<typename T>
T testTemplate(vector<T>& x1)
T testTemplate(std::vector< T >& x1)
{
return x1[0];
}
int main()
{
vector<int> v(10,9);
std::vector< int > v(10, 9);
or
using namespace std;
vector< int > v(10, 9);
std::cout << testTemplate(v) << std::endl;
}
The compiler shows the following output:
CL /nologo /G5 /MDd /W4 /GX /Od /FD /D "WIN32" /D "_DEBUG" /D
"_WINDOWS" /D "_MBCS" /c ..\test.cpp
C:\WATCOM\H\vector(50): Error! E350: col(51) non-type parameter
supplied for a type argument
C:\WATCOM\H\vector(50): Note! N393: col(51) included from ..
\test.cpp(1)
..\test.cpp(15): Error! E651: col(34) cannot instantiate testTemplate
..\test.cpp(6): Note! N649: col(3) template function '?
testTemplate( std::vector<?,<error>> & )' defined in: ..\test.cpp(6)
(col 3)
Thanks for your help.
Chris
.
|
|
|
| User: "Chris" |
|
| Title: Re: Newbie question about templates |
26 Jan 2008 03:43:45 AM |
|
|
Hi,
This code compiles with the Borland compiler, but not with the
OpenWatcom compiler. I am not sure why.
I will use the Borland compiler for now.
Thanks for your help.
Regards
Chris
.
|
|
|
|
|
|
|
|
Related Articles |
|
|
