Newbie question about templates

[Chris]

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

 

[Pascal Bourguignon]

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?

 

[Salt_Peter]

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
*/

 

[Chris]

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

 

[Salt_Peter]

Thanks for your replies. Here is my complete code.

#include <vector>
#include <iostream.h>

using namespace std;

instead of using namespace...

template<typename T>
T testTemplate(vector<T>& x1)

{
return x1[0];

}

int main()
{
vector<int> v(10,9);

std::vector< int > v(10, 9);

or

using namespace std;

 

[Chris]

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