Re: pure virtual function in template class

From:
Mike -- Email Ignored <m_d_berger_1900@yahoo.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 10 Jul 2008 14:52:49 GMT
Message-ID:
<5npdk.809$713.538@trnddc03>
On Thu, 10 Jul 2008 05:53:45 -0700, puzzlecracker wrote:

On Jul 10, 8:49 am, Mike -- Email Ignored <m_d_berger_1...@yahoo.com>
wrote:

Is a pure virtual function in allowed in a template base class? In any
case, I have one working. Am I skating on thin ice?
Thanks,
Mike.


Yes, it can be in the template class, but it can NOT be a virtual
template member function


I don't understand how it could be pure, but not a member.
In any case, here is code that works on my system showing
exactly what I mean.
Mike.

// virt_temp.cc 07/10/08
#include <iostream>
using namespace std;

template <class TYP>
class BaseT
{
protected:
   BaseT(TYP x,TYP y) : x_(x),y_(y){}
   void doAll(){cout << "x_="<<x_<<',';doChild(y_);cout<<endl;}
   virtual void doChild(TYP a)=0;// pure virtual member function
private:
   TYP x_;
   TYP y_;
};

class Child : protected BaseT<int>
{
public:
   Child() : BaseT<int>(1,2){}
   void doThings(){doAll();}
private:
   virtual void doChild(int a);
};

void Child::doChild(int a){cout<<"a="<<a;}

int main(int argc, const char* argv[])
{
   Child child;
   child.doThings();
}

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