inheritance with templates trouble

[richard]

Sorry if this is an obvious question, but I try to let a template class
inherit another template class.

The code here under is a simplification of how I try to do that, but
the compiler complains that 'c' in line '30 ' wasn't declared.

" (g++)
test.h: In member function ‘T Test2<T>::give( )’:
test.h:30: error: ‘c’ was not declared in this scope
"

I have absolute no idea what the problem and/or solution is, can anybody
help me with that please?

Thank you,
Driehoek


////////////////////////////////////////
4: template <class T>
5: class Test
6: {
7: public:
8: virtual void
9: set (T i)
10: {
11: c = i;
12:
13: }
14: virtual T
15: give ()
16: {
17: return c;
18: }
19: protected:
20: T c;
21: };
22:
23: template <class T>
24: class Test2 : public Test<T>
25: {
26: public:
27: T
28: give ()
29: {
30: return c * 2;
31: }
32: };
////////////////////////////////////////

[richard]

Re: inheritance with templates trouble

On Fri, 08 Aug 2008 12:55:21 +0000, richard wrote:

Finally I brute forced the solution :), I had to change line 30 to:

////
return Test<T>::c * 2;
////

But I don't really see the logic in this, why do you need to specify the
base class?

Thanks.

[Stuart Golodetz]

Re: inheritance with templates trouble

"richard" <rafeltjerafela ar@dse.nlwrote in message news:ZmXmk.151$ au1.146@read4.i net.fi...

Sorry if this is an obvious question, but I try to let a template class
inherit another template class.

The code here under is a simplification of how I try to do that, but
the compiler complains that 'c' in line '30 ' wasn't declared.

" (g++)
test.h: In member function â?~T Test2<T>::give( )â?T:
test.h:30: error: â?~câ?T was not declared in this scope
"

I have absolute no idea what the problem and/or solution is, can anybody
help me with that please?

Thank you,
Driehoek


////////////////////////////////////////
4: template <class T>
5: class Test
6: {
7: public:
8: virtual void
9: set (T i)
10: {
11: c = i;
12:
13: }
14: virtual T
15: give ()
16: {
17: return c;
18: }
19: protected:
20: T c;
21: };
22:
23: template <class T>
24: class Test2 : public Test<T>
25: {
26: public:
27: T
28: give ()
29: {
30: return c * 2;
31: }
32: };
////////////////////////////////////////

I think c's a dependent name: you want "this->c" rather than just "c".

HTH,
Stu

[Victor Bazarov]

Re: inheritance with templates trouble

richard wrote:

On Fri, 08 Aug 2008 12:55:21 +0000, richard wrote:
>
Finally I brute forced the solution :), I had to change line 30 to:
>
////
return Test<T>::c * 2;
////
>
But I don't really see the logic in this, why do you need to specify the
base class?

Search the FAQ for "dependent names".

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[richard]

Re: inheritance with templates trouble

On Fri, 08 Aug 2008 09:41:59 -0400, Victor Bazarov wrote:

Thank you, now it makes sense to me.