problem using for_each with member function of abstract class

From:
piwi <bruno.lemarchand@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Fri, 13 Feb 2009 01:43:34 CST
Message-ID:
<dbdd5260-b80e-4c94-8173-20d98bff7ef1@h5g2000yqh.googlegroups.com>
Hello,

As shown in the sample below, I have a vector of a POD in a class.
This class is abstract. I want to implement a print method for the
vector, but managed at the class' level, and using the for_each
algorithm.

struct Bar { /* ... */ };

class Foo
{
public:
  Foo() {}
  virtual ~Foo() {} = 0

public:
  void print(FILE* output) const;
private:
  void printBar(Bar const& bar) const;

private:
  std::vector<Bar> _v;
};

void
Foo::print(FILE* output)
{
  std::for_each(_v.begin(), _v.end(), std::bind1st(std::mem_fun_ref
(&Foo::printBar), *this));
}

Sooo.... Here is my problem: I cannot provide *this in the line above,
because it causes the compiler to fail (reference to reference is
illegal). I cannot instantiate Foo as-is because it is abstract. And I
cannot put printBar in struct Bar because I have specific processing
that is handled by Foo's derived classes.

Is there any workaround that would allow me to call Foo::printBar in
the for_each algorithm?

Thanks !

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