hello, i have a class template

template <class _cType> class t3dpoint {
	public:
_cType x;
_cType y;
_cType z;
};

now when it was just simple struct i could do

t3dpoint __fastcall vectorAB(t3dpoint A,t3dpoint B)
{
t3dpoint result;
result.x = B.x-A.x;
result.y = B.y-A.y;
result.z = B.z-A.z;
return result;
}

i came out with that thing i have no idea what should i write:

template <class type> t3dpoint<type> vectorAB(type A, type B)
{
t3dpoint<type>  result;
result.x = B.x-A.x;
result.y = B.y-A.y;
result.z = B.z-A.z;
return result;
}

so how should i deal with this

ok but how to write this

template <class type> t3dpoint<type> vectorAB(t3dpoint<type> A, t3dpoint<type> B)

becasue i have no idea what to put before vectorAB(t3dpoint<type> A, t3dpoint<type> B)

well it doesnt throw any errors on compile but i am changing the whole project to use templates and it needs lot of recoding so.. so i started another project and tried to use it

results drive me mad:

header

template <class _cType> class t3dpoint {
	public:
_cType x;
_cType y;
_cType z;
};

cpp

template <class type> t3dpoint<type> vectorAB(t3dpoint<type> A, t3dpoint<type> B)
{
t3dpoint<type>  result;
result.x = B.x-A.x;
result.y = B.y-A.y;
result.z = B.z-A.z;
return result;
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  t3dpoint <float> rA;
  t3dpoint <float> rB;
  rA.x = 0.0;
  rA.y = -1.0;
  rA.z = 0.2;

  rB.x = 0.0;
  rA.y = 0.0;
  rA.z = 0.0;

t3dpoint <float> res = vectorAB(rA,rB);

}

res.x = 0

res.y = 3.07155392358416E33

res.z = 1.09585508442014E33

sometimes they change to different numbers

EDIT

now it works i had a bug in the code

rB.x = 0.0; rA.y = 0.0; rA.z = 0.0; instead of rB.y and rB.z ok it works

thanks for help!

Don't use underscores as a suffix prefix. note to self: don't post without coffee.

• Reserved in any scope, including for use as implementation macros:
  • identifiers beginning with an underscore and an uppercase letter
  • identifiers containing adjacent underscores (or "double underscore")
• Reserved in the global namespaces:
  • identifiers beginning with an underscore

Don't use underscores as a suffix.

Sorry to hijack a little, but I've seen header guards in the form of:

#ifndef __HEADER_HPP__
#define __HEADER_HPP__
#endif

Is that forbidden because it's using two adjacent underscores?

Don't use underscores as a suffix.

Using underscores as a suffix is ok, as long you avoid adjacent underscores.

What WiredCat is doing is using them as a prefix, which you shouldn't (as per ChaosEngine's quote).

Suffix = at the end.

Prefix = at the beginning.

As per ChaosEngine's quote, WirdsCar's usage of the underscore is technically fine. It does not contain adjacent underscores, no leading underscore followed by an upper case letter, and no underscores at global scope. Not that I recommend using it anyway.

True, my mind just blanked out the "followed by uppercase" part.