Re: anti-standard code can compile -- about template class

From:

Norbert Unterberg <nunterberg@newsgroups.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 07 Mar 2008 15:10:07 +0100

Message-ID:

<#hHkzzFgIHA.1188@TK2MSFTNGP04.phx.gbl>

George schrieb:

I have tried if we try to instantise the code I posted in my original
question, it can not compile. Here is my code. Does this compile error
because of VC will look for global i other than base class i? I do not know
why if the class is instantised, still the global i other than base class i
is looked for?

I tried instanciating Derived<int> in your original code, and the code
you posted in your last mail.

Both compile and work as expected. No compiler error.

Norbert

here is the compile error message. It is appreciated if you could review my
code and comment?

1>d:\visual studio 2008\projects\test_template4\test_template4\main.cpp(20)
: error C2065: 'i' : undeclared identifier
1> d:\visual studio 2008\projects\test_template4\test_template4\main.cpp(20)
: while compiling class template member function 'int Derived<T>::get_i(void)'
1> with
1> [
1> T=int
1> ]
1> d:\visual studio 2008\projects\test_template4\test_template4\main.cpp(25)
: see reference to class template instantiation 'Derived<T>' being compiled
1> with
1> [
1> T=int
1> ]

[Code]

#include <iostream>

using namespace std;

template <typename T> struct Base {
public:
    Base (int _i): i (_i)
    {

    }

    int i;
};

template <typename T> struct Derived : public Base<T> {
public:
    Derived (int _i) : Base<T> (_i)
    {
    }
    int get_i() { return i; }
};

int main()
{
    Derived<int> d (200);
    cout << d.get_i() << endl; // output 200
    return 0;
}
[/Code]

regards,
George