View source for C program for neutron efficiency

 #include <iostream>
 #include <cmath>
 using namespace std;

 double crossSectionHydrogenFunction();
 double numberCarbonFunction(double thickness, 
                             const double CUBICCENTIMETERCARBON);
 double numberHydrogenFunction(double thickness, 
                               const double CUBICCENTIMETERHYDROGEN);
 double crossSectionCarbonFunction();
 void efficiencyFunction(double numberHydrogen, double numberCarbon, 
                         double crossSectionHydrogen, double crossSectionCarbon, 
                         double thickness);

 <code>/************************************************************************
 * This program is to find the
 * efficiency of a neutron detector.
 ************************************************************************/
 double  main()
 {</code>
   double neutronEnergy;
   double numberHydrogen;
   double numberCarbon;
   double crossSectionHydrogen;
   double crossSectionCarbon;
   double thickness;
   const double CUBICCENTIMETERCARBON = 5.23e22;
   const double CUBICCENTIMETERHYDROGEN = 4.74e22;

   cout << endl;
   cout << "Enter thickness of detector (in centimeters): ";
   cin >> thickness;

   crossSectionHydrogen = crossSectionHydrogenFunction();
   numberCarbon = numberCarbonFunction(thickness,
                                       CUBICCENTIMETERCARBON);
   numberHydrogen = numberHydrogenFunction(thickness,
                                           CUBICCENTIMETERHYDROGEN);
   crossSectionCarbon = crossSectionCarbonFunction();

   efficiencyFunction(numberHydrogen, numberCarbon,
                      crossSectionHydrogen, crossSectionCarbon,
                      thickness);
 }

 /**********************************************************************
  * Equation for cross section of hydrogen according to
  * equation 15-9 from Radiation Detection and Measurement
  *                                   by Glenn Knoll
  *********************************************************************/
  double crossSectionHydrogenFunction()
  {
    double neutronEnergy;
    double crossSectionHydrogen;

    cout << endl;
    cout << "Enter neutron energy (in MeV): ";
    cin >> neutronEnergy;

    crossSectionHydrogen = ((4.83e-24 / sqrt(neutronEnergy))
                              - .578e-24);

    return crossSectionHydrogen;
  }

 /**********************************************************************
  * Equation for calculating the number of Carbons in
  * the problem per cubic centimeter, dependent on what
  * the user put in for the thickness of the detector.
  *********************************************************************/
  double numberCarbonFunction(double thickness, const
                              double CUBICCENTIMETERCARBON)
  {
    double numberCarbon;

    numberCarbon = CUBICCENTIMETERCARBON;
    return numberCarbon;
  } 

 /*********************************************************************
  * Equation for calculating the number of Hydrogens in
  * the problem per cubic centimeter, dependent on what
  *  the user put in for the thickness of the detector.
  ********************************************************************/
  double numberHydrogenFunction(double thickness, const
                                double CUBICCENTIMETERHYDROGEN)
  {
    double numberHydrogen;

    numberHydrogen = CUBICCENTIMETERHYDROGEN;
    return numberHydrogen;
  }

 /*********************************************************************
  * Requesting the cross section from the Knoll book, and
  * then calculating it from barns to centimeters.
  ********************************************************************/
  double crossSectionCarbonFunction()
  {
    double crossSectionCarbon;

    cout << endl;
    cout << "Enter the cross section of Carbon by "
         << "looking in Radiation" << endl
         << "Detection and Measurement by Glenn Knoll, on"
         << " page 535, " << endl
         << "Figure 15-15b (in barns): ";
    cin >> crossSectionCarbon;
    crosSectionCarbon = crossSectionCarbon * 1e-24;

    return crossSectionCarbon;
  }

 /*******************************************************************
  * Equation for efficiency according to equation 15-8b
  * from Radiation Detection and Measurement
  *                            by Glenn Knoll
  ******************************************************************/
  void efficiencyFunction(double numberHydrogen, double
                          numberCarbon, double crossSectionHydrogen,
                          double crossSectionCarbon, double
                          thickness)
  {
    double efficiency;
    double nHcH = numberHydrogen * crossSectionHydrogen;
    double nCcC = numberCarbon * crossSectionCarbon;

    efficiency = (((nHcH) / (nHcH + nCcC)) * (1-exp(-(nHcH
                                                   + nCcC)
                                             * thickness)));
    if(efficiency <= 0)
    {
      efficiency = 0;
    }
    cout.precision(4);
    cout << endl;
    cout << "Therefore, the efficiency of our "
         << "system is: " << efficiency *100 << "%" << endl;
    cout << endl;
    return;
  }