//******************************************************************
//   HEADER FILE for program hpvplot.cpp                           *
//   FILENAME:      hpvplot.h                                      *
//   PROGRAMMER:    Dr.Iz (Urieli)                                 *
//   DATE:          01/17/04  (updated 10/7/2007)                  *
//******************************************************************
using namespace std;
class HPvehicle { // human powered vehicle
  private:
    float cda,     // [sq.m] - (coefficient of drag * frontal area)
          cr,      // [-] - coefficient of rolling resistance
          mass;    // [kg] - mass of hpv + rider
  public:
    float g,        // [m/s/s] - acceleration due to gravity
          density,  // [kg/cu.m] - air density
          wind_mph, // [mph] - wind velocity (positive for headwind)
          slope;    // [-] - height/distance - (positive for uphill)
    //===============================================================
    HPvehicle( // Constructor initialization
       float mass0 = 92.0,  // [kg] - 15 kg bike, 80 kg rider typical
       float cda0 = 0.4, // [sq.m] - upright city bicycle
       float cr0 = 0.005) // [-] - high pressure tires on flat road
    { 
       mass = mass0;
       cda = cda0;
       cr = cr0;
       cout << "hpv initialised as follows:\n"
            << " mass (hpv + rider): " << mass << "[kg]\n"
            << " cda (coeff.drag*area): " << cda << "[sq.m]\n"
            << " cr (coeff.rolling resist): " << cr << endl;
       g = 9.807; // [m/s/s] - standard acceleration due to gravity
       density = 1.18; // [kg/cu.m] - sea level standard air density
       wind_mph = slope = 0;
       cout << "local conditions initialised as follws:\n"
            << " gravity acceleration: " << g << "[m/s/s]\n"
            << " air density: " << density << "[kg/cu.m]\n"
            << " wind velocity: " << wind_mph << "[mph]\n"
            << " slope: " << slope << endl;
       cout << "-----------------------------------------------------\n";
    }
    //===============================================================
    float find_power(float vel_mph)
    {  // applied power [watts] as function of velocity [mph]
       // pre: argument vel_mph and all private and public variables
       //      have values
       // post: power (watts) has been evaluated and returned
       const float CONVERT = (4.0/9.0); // mph to meters/sec
       float vel, // velocity converted to m/s  
             wvel, // wind velocity converted to m/s 
             drag, // resistance due to wind drag [N]
             resist, // resistance due to rolling and slope [N]
             power; // applied power to wheels [watts]

       vel = CONVERT * vel_mph;
       wvel = CONVERT * wind_mph;
       drag = cda*density*(vel + wvel)*(vel + wvel)/2.0;
       resist = mass*g*(cr + slope);
       power = vel*(drag + resist);

       return power;
    }
    //===============================================================
    float find_vel(float power, 
                    float lo_vel, float hi_vel, float epsilon);
         // "power" the required power applied to hpv
         // find the velocity (root of {find_power - power}) within
         // the bounds [lo_vel,hi_vel] within error bound "epsilon"
    //===============================================================
    float dif_power(float vel, float power){
         // returns difference in power - used in the find_vel method
          return (find_power(vel) - power);
    }
    //===============================================================
    void funarrays(float lo_vel, float hi_vel, 
                   float vel[], float pow[], int n);
    //   creates two coordinate arrays of n components: velocity (vel)
    //   and power (pow), for (n-1) equally divided velocity intervals 
    //   between lo_vel and hi_vel.
    //===========================================================
    void savearrays(float vel[], float pow[], int n);
    //   save the two arrays on a data file in two columns 
    //   separated by tabs. The filename is entered from the keyboard.
    //===========================================================
};
//================================================================
int const SIZE = 100; // maximum size of the arrays 

// general function prototypes:
float get_wind(void); // get the wind velocity from the keyboard
float get_slope(void); // get the slope from the keyboard
void getbike(float& mass, float& cda, float& cr);
     // get the bike data from a bikefile
//====================================================================