I have a couple of template classes "Stats<T>" and "Numerical<T>" within a "Statistics" namespace. The Numerical<T> class inherits publicly from Stats<T>. They are defined as below.

namespace Statistics { //declare Statistics namespace
  template <typename T> class Stats {
  protected:
    vector<T> dataSet;  //contains the actual data set to be analyzed
    /* ... other members and declarations ... */

  };  //end Stats Class

  template <typename T> class Numerical : public Stats<T> {
  protected:
    double mean;        //the numeric average
    /* ... other members ... */

    void updateMean();  //called by other methods to update the mean when necessary
    /* ... other declarations ... */

  };  //end Numerical Class
} //end Statistics namespace

Now here's where the question comes in. I'm working on the implementation of Numerical<T>::updateMean(), and based on the class structure above, the method should have access to the dataSet vector. The problem that I'm having is that I seem to have to resolve the Stats class every time I want to use one of its members from Numerical. I don't remember having to do that before.

Is this normal? Or is there some nuance that I'm missing somewhere? Do I need to add some sort of using statement(s) to the Numerical class?

Implementation of method:

namespace Statistics { //declare Statistics namespace

  /* ... other implementations ... */

  template <typename T> void Numerical<T>::updateMean() {
    vector<T>::const_iterator cpData;
    double sigma = 0.0;
    if (Stats::dataSet.size() == 0) {
      this->mean = 0.0;
      return;
    }
    for (cpData = Stats::dataSet.begin(); cpData != Stats::dataSet.end(); ++cpData) {
      sigma += (*cpData);
    }
    mean = (sigma / Stats::dataSet.size());
  }

  /* ... other implementations ... */

} //end Statistics namespace

I foresee this same issue extending to every other method as well. I know how to deal with it if necessary, but if I can avoid it altogether that would be great.

http://www.parashift.com/c++-faq-lite/templates.html#faq-35.19

Thanks for the link. The suggestions there really helped. I wound up pulling 'this' out of the toolbox.

Not sure if this has addressed all the issues yet. I'll have to get back with.

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