// This is a version that I coded of the CS-071 Project 1 for the
// Fall 2002 semester.
// Nathaniel Guy, September 2002

// Basically I take a lot of trends and combine them into one program
// that takes data and predicts the concentration by a set formula.
// It's pluggy and chuggy, but the algorithm took some thinking. I
// tried to make the program's operations as simple and straight-forward
// as possible.

#include<iostream.h>

int main(){
  const float maxconcentration = 2100;
  float watertemp, salinity, light, nutrients;

  // data collection jive

  cout << "Welcome to the pseudo-nitzschia australis concentration "
       << "estimator." << endl;
  cout << "Given conditions in Monterey Bay, an estimation will be made "
       << "as to the probable" << endl << "concentration of the diatom."
       << endl << endl;
  cout << "Please input the average water temperature in degrees C: ";
  cin >> watertemp;
  cout << "Please input the water salinity in ppm: ";
  cin >> salinity;
  cout << "Please input the average amount of light in lumens: ";
  cin >> light;
  cout << "Please input the nitrate nutrients in mg/m^3: ";
  cin >> nutrients;

  // note on algorithm: for simplicity, I assumed that all factors were
  // equally important and affected the overall concentration by a factor
  // of 1/4. Further information and research would be necessary to make
  // user, but that might make the program in general less efficient and
  // it'd be a lot easier just to set constants for the ratio. Naturally,
  // this is left as an exercise to the reader. Also, I eventually ended
  // up utilizing a simple parabola to map the temperature curve; the
  // data seemed to be describing its behavior to be parabolic in nature.
        
  // below, adjusting of variables for the sake of the algorithm
        
  // since the functional effect of the water temperature is only in
  // place from 10 to 22 degrees C, I decided to seal those bounds:

  if (watertemp < 10)
    watertemp = 10;
  else if (watertemp > 22)
    watertemp = 22;

  // and thusly with the salinity, from 32 to 27 ppm:

  if (salinity < 32)
    salinity = 32;
  else if (salinity > 37)
    salinity = 37;

  // similarly with the light, which runs from 600 to 1350 lumens:

  if (light < 600)
    light = 600;
  else if (light > 1350)
    light = 1350;

  // and finally the same with the nutrients, from 0 to 25 mg/m^3:

  if (nutrients < 0)
    nutrients = 0;
  else if (nutrients > 25)
    nutrients = 25;

  // now to the calculation of the actual result:


  float concentration = maxconcentration * 
    /* temp. factor*/    
    ((-.027777) * (watertemp - 16) * (watertemp - 16) + 1) *
    /* salinity factor */
    ((37 - salinity) / 5) *
    /* light factor */
    ((light - 600) / 750) *
    /* nutrients factor */
    (nutrients / 25);

  cout << "We estimate the amount of pseudo-nitzschia australis "
       << "(in mg/m^3) to be: " << concentration << endl;

  return 0;
}