## digitalmars.D.learn - accessing numeric template parameters

```If I have a struct with numeric template parameter, how can I
access it within member functions? Like normal member variables?

struct polynomial(uint base)
{
private:
uint[] N;
public:
this(uint x) { base = x; }
...
{
if(N.length < P.N.length) N.length = P.N.length;
foreach(i; 0..P.N.length)
{
N[i] = (N[i]+P.N[i]) % base;
}
}
}

This doesn't work for me :-/
```
Nov 03 2014
```On Monday, 3 November 2014 at 14:27:47 UTC, Dominikus Dittes
Scherkl wrote:
If I have a struct with numeric template parameter, how can I
access it within member functions? Like normal member
variables? And how about the constructor?

struct polynomial(uint base)
{
private:
uint[] N;
public:
this(uint x) { base = x; }
...
{
if(N.length < P.N.length) N.length = P.N.length;
foreach(i; 0..P.N.length)
{
N[i] = (N[i]+P.N[i]) % base;
}
}
}

This doesn't work for me :-/

You cannot assign to it, because it is only avaliable during
compilation. Think of it as an immediate value, not variable.
```
Nov 03 2014
```On Mon, Nov 3, 2014 at 3:27 PM, Dominikus Dittes Scherkl via
Digitalmars-d-learn <digitalmars-d-learn puremagic.com> wrote:
If I have a struct with numeric template parameter, how can I access it
within member functions? Like normal member variables? And how about the
constructor?

struct polynomial(uint base)
{
private:
uint[] N;
public:
this(uint x) { base = x; }

base is part of the type. polynomial is just a 'recipe' for a type,
the real struct would be Polynomial!(0), Polynomial!(1), etc. Note
that Polynomial!0, Polynomial!1, ... are all different types.

Being part of the type means it's defined only at compile-time, you
cannot use a runtime value (like 'x') to initialize it.

Note that with your current code, `base' is not visible outside
Polynomial. You can alias it to a field to make it visible:

struct Polynomial(uint base)
{
alias b = base; // b is visible outside (but set at compile-time !)
...
}

You can create one like this:

Polynomial!2 poly;
poly.N = [0,1,0,0,1,1];

assert(poly.b == 2);

Of course, you cannot change b: `poly.b = 3;' is forbidden.
```
Nov 03 2014
```On Monday, 3 November 2014 at 21:17:09 UTC, Philippe Sigaud via
Digitalmars-d-learn wrote:
struct polynomial(uint base)
{
private:
uint[] N;
public:
this(uint x) { base = x; }

base is part of the type. polynomial is just a 'recipe' for a
type,
the real struct would be Polynomial!(0), Polynomial!(1), etc.
Note
that Polynomial!0, Polynomial!1, ... are all different types.

Yes, that's what I intend.
Being part of the type means it's defined only at compile-time,
you
cannot use a runtime value (like 'x') to initialize it.

Note that with your current code, `base' is not visible outside
Polynomial. You can alias it to a field to make it visible:

struct Polynomial(uint base)
{
alias b = base; // b is visible outside (but set at

Ah, ok. Thank you!

compile-time !)
...
}

You can create one like this:

Polynomial!2 poly;
poly.N = [0,1,0,0,1,1];

Ok, now I remember, struct doesn't need an explicit constructor.
(in this case)
```
Nov 05 2014