complex in header file?

[chuan]

#ifndef _GLUEBALL_H
#define _GLUEBALL_H

#include <complex>

static const complex<int> gamma5[16] =
{ 0,0,1,0, 0,0,0,1, 1,0,0,0, 0,1,0,0 };

#endif


I have error during compiling:
error: expected constructor, destructor, or type conversions before
`<' token


why????

 

[joshuamaurice]

#ifndef _GLUEBALL_H
#define _GLUEBALL_H

#include <complex>

static const complex<int> gamma5[16] =
  { 0,0,1,0, 0,0,0,1, 1,0,0,0, 0,1,0,0 };

#endif

I have error during compiling:
error: expected constructor, destructor, or type conversions before
`<' token

Bad error message from the compiler.
http://www.comeaucomputing.com/tryitout/
gives a much better one.

You want std::complex. complex is a name in a namespace, so you need
to do one of the following:
using namespace std;
using std::complex;
std::complex

Also, don't use names starting with underscores. All global names
starting with underscores are reserved for the implementation (as are
some other names in other scopes), so it's considered bad practice to
ever use a name starting with an underscore, and in your case produces
undefined behavior (?).

 

[Richard Herring]

In message

#ifndef _GLUEBALL_H
#define _GLUEBALL_H

#include <complex>

static const complex<int> gamma5[16] =
  { 0,0,1,0, 0,0,0,1, 1,0,0,0, 0,1,0,0 };

#endif

I have error during compiling:
error: expected constructor, destructor, or type conversions before
`<' token

Bad error message from the compiler.
http://www.comeaucomputing.com/tryitout/
gives a much better one.

You want std::complex. complex is a name in a namespace, so you need
to do one of the following:
using namespace std;
using std::complex;
std::complex

Also, don't use names starting with underscores. All global names
starting with underscores are reserved for the implementation (as are
some other names in other scopes), so it's considered bad practice to
ever use a name starting with an underscore, and in your case produces
undefined behavior (?).

And what on earth are the semantics of std::complex<int> going to be?
std::complex is only intended to be instantiated on floating-point
types, or its behaviour will be so different from that of ordinary
complex numbers that you should be calling it something else.

26.2/2:

The effect of instantiating the template complex for any type other than
float, double or long double is unspecified.