pretty print of boost::multi_array example fails - c++

Question

I have this smart and cool example:
#include <iostream>
#include "boost/multi_array.hpp"
#include "boost/array.hpp"
#include "boost/cstdlib.hpp"
template <typename Array>
void print(std::ostream& os, const Array& A)
{
typename Array::const_iterator i;
os << "[";
for (i = A.begin(); i != A.end(); ++i) {
print(os, *i);
if (boost::next(i) != A.end())
os << ',';
}
os << "]";
}
void print(std::ostream& os, const double& x)
{
os << x;
}
int main()
{
typedef boost::multi_array<double, 2> array;
double values[] = {
0, 1, 2,
3, 4, 5
};
const int values_size=6;
array A(boost::extents[2][3]);
A.assign(values,values+values_size);
print(std::cout, A);
return boost::exit_success;
}
But if I try to compile it: g++ -I/usr/include/boost/ b.cpp I get this error:
b.cpp: In function ‘void print(std::ostream&, const Array&) [with Array = double]’:
b.cpp:12: instantiated from ‘void print(std::ostream&, const Array&) [with Array = boost::detail::multi_array::const_sub_array<double, 1u, const double*>]’
b.cpp:12: instantiated from ‘void print(std::ostream&, const Array&) [with Array = main()::array]’
b.cpp:32: instantiated from here
b.cpp:9: error: ‘double’ is not a class, struct, or union type
b.cpp:11: error: request for member ‘begin’ in ‘A’, which is of non-class type ‘const double’
b.cpp:9: error: ‘double’ is not a class, struct, or union type
b.cpp:9: error: request for member ‘end’ in ‘A’, which is of non-class type ‘const double’
b.cpp:9: error: ‘double’ is not a class, struct, or union type
b.cpp:9: error: ‘double’ is not a class, struct, or union type
b.cpp:9: error: ‘double’ is not a class, struct, or union type
b.cpp:13: error: request for member ‘end’ in ‘A’, which is of non-class type ‘const double’
b.cpp:9: error: ‘double’ is not a class, struct, or union type
shell returned 1
What was wrong? It seems to not understand the difference between the first and the second print function. Maybe some compiler options I missed?
EDIT:
If i use template<> as Craig H answer i resolve the problem in a isolated example.cpp. But if i put the 2 functions in a separate .h file in my project, the error appears again!

Answer 1

In this example you created a template function as your first print function then declare another function that implements a specific version of that template without template specializing. I think if you change the following line
void print(std::ostream& os, const double& x)
to
template<> void print<double>(std::ostream& os, const double& x)
your problem should go away.