---

Action.h

Go to the documentation of this file.

/*
    File:           Action.h

    Function:       Defines an 'Action' which can be applied to all members of
                    a container.
                    
    Author(s):      Andrew Willmott

    Copyright:      (c) 1995-2000, Andrew Willmott
 */

#ifndef __Action__
#define __Action__

#include "cl/Basics.h"

#define TAction Action<T>


// --- Abstract Action Class ---------------------------------------------------


template <class T> class Action
{
public: 
        
    virtual Void    Start() {};
    virtual Void    Process(T &t) = 0;              // Abstract action method.
    virtual Void    Stop() {};
};


// --- A demonstration Action --------------------------------------------


template <class T> class StatsFinder : public Action<T>
{
public:
    
    Void    Start();
    Void    Process(T &t);              
    Void    Stop();
    
    T       mean;
    T       variance;
    
protected:
    
    Int     n;
    T       sumX;
    T       sumXSqr;
};


template <class T> Void StatsFinder<T>::Start()
{
    sumX = sumXSqr = 0;
    n = 0;
}
    
template <class T> Void StatsFinder<T>::Process(T &t)
{
    sumX += t;
    sumXSqr += sqr(t);
    n++;
}
    
template <class T> Void StatsFinder<T>::Stop()
{
    mean = sumX / n;
    variance = sumXSqr / n - sqr(mean);
}
    
#endif

---