//*************************************************************
//  Filename:      shutarray.h                                *
//  Programmer:    Dr.Iz (Urieli)                             *
//  Date:          09/29/03                                   *
//*************************************************************
using namespace std;
class Shuttle { // space shuttle upward velocity and height from liftoff.
                // After separation we follow the empty booster shells.
  private:
    float m_total, // [kg] shuttle + fuel + payload at liftoff
          m_fuel, // [kg] solid fuel in boosters at liftoff
          v_boost, // [m/s] ejection velocity booster rockets
          q_boost, // [kg/s] ejection mass flow booster rockets
          v_orbit, // [m/s] ejection velocity orbiter engines
          q_orbit; // [kg/s] ejection mass flow orbiter engines
  public:
    float gravity; // [m/s^2] gravity acceleration
    //===================================================================
    Shuttle(float mt = 2034681.0) // [kg] assuming 20,000kg payload
    { // Constructor initialization:
        m_total = mt;
        m_fuel = 1004250.0; // [kg] total initial solid fuel
        v_boost = 2817.0; // [m/s] ejection velocity boosters
        q_boost = 8369.0; // [kg/s] ejection mass flow boosters
        v_orbit = 3636.0; // [m/s] ejection velocity
        q_orbit = 1378.0; // [kg/s] ejection mass flow boosters
        gravity = 9.807; // [m/s^2] acceleration due to gravity
        cout << "Shuttle initialized as follows:\n"
             << " total mass at liftoff: " << m_total << "[kg]\n";
        cout << " mass of solid fuel at liftoff: " << m_fuel << "[kg]\n";
        cout << " booster ejection fuel velocity: " << v_boost << "[m/s],\n"
             << "       mass flow rate: " << q_boost << "[kg/s]\n";
        cout << " orbiter ejection fuel velocity: " << v_orbit << "[m/s],\n"
             << "       mass flow rate: " << q_orbit << "[kg/s]\n";
        cout << " initial gravity acceleration: " << setprecision(3)
             << gravity << "[m/s^2]\n" << setprecision(1);
    }
    //===================================================================
    float find_velocity(float etime) {
       // [m/s] upward velocity of shuttle from liftoff
       // pre: all private and public variables above have values
       //      argument etime (elapsed time) has a value
       // post: value of upward velocity (velo) has been returned
       // Note: On separation we follow the empty boosters.
       float booster, // velocity component due to booster
             orbiter, // velocity component due to orbiter
             velo, // net upward velocity of shuttle system
             vchar; // characteristic velocity of shuttle and boosters

       float tb = m_fuel/q_boost; // time to "brennschluss"
       if(etime < tb) {
          booster = v_boost*log(m_total/(m_total - q_boost*etime));
          orbiter = v_orbit*log(m_total/(m_total - q_orbit*etime));
          velo = orbiter + booster - gravity*etime;
       }
       else {
          booster = v_boost*log(m_total/(m_total - m_fuel));
          orbiter = v_orbit*log(m_total/(m_total - q_orbit*tb));
          vchar = orbiter + booster;
          velo = vchar - gravity*etime;
       }
       return velo; // [m/s]
    }
    //===========================================================
    float find_height(float etime);
       // height [m] of shuttle from liftoff
       // etime [s] - elapsed time from liftoff.
       // Note: On separation we follow the empty boosters.
    //===========================================================
    void funarrays(float etime, int n,
                   float time[], float vel[], float height[]);
    //   creates three coordinate arrays of n components: time, velocity
    //   and height, for equally divided time intervals between liftoff
    //   and the elapsed time interval.
    //===========================================================
    void printarrays(float time[], float vel[], float height[], int n);
    // prints three columns of the corresponding array elements
    //===========================================================
    void savearrays(float time[], float vel[], float height[], int n);
    //   save the three arrays on a data file in three columns
    //   separated by tabs. The filename is entered from the keyboard.
    //===========================================================
};
//================================================================
void get_mass(float& mass);
   // get the Shuttle total initial mass from the \"shuttle.mass\" file\n";
   // pre: text data file "shuttle.mass" exists (else program aborts)
   // post: reference argument mass has a value
//========================================================================
void minmax(float y[], int n, float& ymin, float& ymax);
// finds minimum and maximum elements of y array
//========================================================================
int const SIZE = 100; // maximum size of the arrays