final class in c++

Question

class Temp
{
private:
    ~Temp() {}
    friend class Final;
};

class Final : virtual public Temp
{
public:
     void fun()
     {
         cout<<\"In base\";         


        

Answer 1

Well, for this program (pleasse provide correct, compilable examples)

#include 

class Temp
{
private:
    ~Temp() {}
    friend class Final;
};

class Final : virtual public Temp
{
public:
    void fun() { std::cout<<"In base"; }
};

class Derived : public Final {};

int main() {
    Derived obj;
    obj.fun();
}

Comeau Online says

Comeau C/C++ 4.3.10.1 (Oct  6 2008 11:28:09) for ONLINE_EVALUATION_BETA2
Copyright 1988-2008 Comeau Computing.  All rights reserved.
MODE:strict errors C++ C++0x_extensions

"ComeauTest.c", line 16: error: "Temp::~Temp()" (declared at line 6) is inaccessible
  class Derived : public Final {
                         ^
          detected during implicit generation of "Derived::Derived()" at line
                    21

"ComeauTest.c", line 16: error: "Temp::~Temp()" (declared at line 6) is inaccessible
  class Derived : public Final {
        ^
          detected during implicit generation of "Derived::~Derived()" at line
                    21

2 errors detected in the compilation of "ComeauTest.c".

Since, when in doubt, I always trust como (I have only ever found one error in it, but many in other compilers), I suppose VC9 (which accepts the code) is in error. (From that void main() I suppose you use VC, too.)