#include "stdstuff.h"
#include "Vector.h"


void realMain () {

  Vector force, r, moment, direction,
         totalForce (0, 0, 0), totalMoment (0, 0, 0);
  int forceCount;

  cout << "Enter number of forces: ";
  cin >> forceCount;

  for (int i = 0; i < forceCount; i++) {

    cout << "Enter i, j, and k for force: ";
    force.read (cin);

    cout << "Enter i, j, and k for point of application: ";
    r.read (cin);

    // totalForce = totalForce + force
    totalForce.add (force);

    // moment = r X force (cross product)
    moment = r.cross (force);

    // totalMoment = totalMoment + moment
    totalMoment.add (moment);

  }

  cout << "The forces are equivalent to the combination of\n  1/. A force of ";
  totalForce.write(cout);
  cout << " applied at the origin and\n  2/. A moment of ";
  totalMoment.write(cout);
  cout << ".\nThe magnitude of the force is " << totalForce.magnitude()
       << ".\n";

  cout << "\nEnter i, j, and k for the direction of interest: ";
  direction.read(cin);

  try {
    // convert the vector entered to a unit vector in the same direction
    direction.unitize ();
    // compute and output totalForce . direction (the dot product)
    cout << "The magnitude of the force in this direction is "
         << totalForce.dot (direction)  // dot product
         << ".\n";
  }
  catch (domain_error &e) {
    // method "unitize" throws a domain_error exception if
    // applied to 0i + 0j + 0k.
    // if we get here, this must have happened.
    cout << "An all zero vector has no direction.\n";
  }

}

int main () {

  try {

    realMain ();

  }
  catch (exception &e) { // catches all uncaught exceptions

    cout << "\nException <" << e.what() << "> occurred.\n";

  }

  pause ();
  return 0;

}