setting default value for template parameter list

[bluekite2000]

I want to accomplish the following

void foo(const T &v1, const T &v2)
{
if(v1&v2 is of type double)
double alpha=1.0;
else if (v1&v2 is of type complex double)
complex double alpha=(1.0,1.0);

bar(v1,v2,alpha);
}

void bar(const T&v1, const T&v2, const T& alpha)
{
}

but dont know how. Please help
Regards,

[Rolf Magnus]

bl**********@gmail.com wrote:

I want to accomplish the following

void foo(const T &v1, const T &v2)
{
if(v1&v2 is of type double)
?? Is foo supposed to be a template?
double alpha=1.0;
else if (v1&v2 is of type complex double)
complex double alpha=(1.0,1.0);
Did you mean std::complex<double>?

bar(v1,v2,alpha);
}

What if v1 and v2 are of neither of those 2 types? Anyway, maybe you are
searching for specialization:

template <typename T>
void foo(const T &v1, const T &v2)
{
//whatever you want the default to be
}

template<>
void foo(const double &v1, const double &v2)
{
const double alpha(1.0);
bar(v1,v2,alpha);
}

template<>
void foo(const std::complex<double> &v1, const std::complex<double> &v2)
{
const std::complex<double> alpha(1.0,1.0);
bar(v1,v2,alpha);
}

[bluekite2000]

foo and bar are both member functions of a class. Will the above syntax
still work?

[Victor Bazarov]

bl**********@gmail.com wrote:

foo and bar are both member functions of a class. Will the above syntax
still work?

Which above syntax? I don't see anything _above_ what you wrote.
[Shit, I begin to sound like Brian]

Yes, the full specialisation of a template member is possible, you just
need to define it outside the class definition.

V

[Default User]

Victor Bazarov wrote:

bl**********@gmail.com wrote:

foo and bar are both member functions of a class. Will the above syntax
still work?

Which above syntax? I don't see anything _above_ what you wrote.
[Shit, I begin to sound like Brian]

It's a GOOD thing.


Brian

[bluekite2000]

I tried the full specialization as suggested
template <typename T>
class Matrix
{
....
Matrix operator * (const Matrix<T>& B);
....
};

template<typename T>
Matrix<T> Matrix<T>::operator *(const Matrix<T>& B)
{
double alpha=1;
....
}

template<>
Matrix<std::complex<float> > Matrix<std::complex<float> >::operator *(
const Matrix<std::complex<float> >& B)
{
std::complex<float> alpha=std::complex<float>(1,0);
....
}

but received an error from gcc
multiple definition of `Matrix<std::complex<float>

::operator*(Matrix<std::complex<float> > const&)

Any idea???

[Rolf Magnus]

Victor Bazarov wrote:

bl**********@gmail.com wrote:

foo and bar are both member functions of a class. Will the above syntax
still work?

Which above syntax? I don't see anything _above_ what you wrote.
[Shit, I begin to sound like Brian]

Yes, the full specialisation of a template member is possible, you just
need to define it outside the class definition.

Since when? I thought if you want to specialize a member, you have to
specialize the whole class.