/* Programmer: Dylan McDonald
   Class &  Section: CS 54, Section <n>
   Date: 11 September, 2001
   Purpose: Break & score balsa wood bridges for the Stimsonian Institute */

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

int main()
{
  bool lightEnough;
  short joints, userChoice = 0;
  double sticks;
  double appliedMass = 0.0, breakScore = 0.0, mass, score;

  /* ask user for bridge specifications */
  cout << "Number of joints: ";
  cin >> joints;
  cout << "Number of 10 cm sticks: ";
  cin >> sticks;

  /* make sure the specifications make sense */
  if (joints < 0)
    joints = -joints;
  if (sticks == 0)
  {
    cout << "You can't build a bridge without sticks. Maybe you've been "
         << "eating too much glue." << endl;
    sticks = 4.2;
  }
  else if (sticks < 0)
    sticks = -sticks;

  /* calculate the mass of the bridge */
  mass = 1.5 * sticks + joints / 2.0;
  cout << "The mass of the bridge is " << mass << " g." << endl;

  /* see if the bridge qualified */
  if (mass <= 25)
    lightEnough = true;
  else
    lightEnough = false;

  /* score the bridge */
  score = (((sticks + joints) * (sticks + joints)) / (mass * sticks))
        * lightEnough;
  if (score > 0.0)
    cout << "The bridge clocked in at " << score << " points." << endl;
  else
    cout << "Surely this is not a bridge over troubled waters!" << endl;


  /* while the bridge isn't broken and the user doesn't want to exit... */
  while (breakScore < (score / 2.0) && userChoice != 5)
  {
    /* ...present the menu of options */
    do
    {
      cout << "Apply Mass to Bridge: " << endl
           << "1) 0.5 kg" << endl
           << "2) 1 kg" << endl
           << "3) 2 kg" << endl
           << "4) 5 kg" << endl
           << "5) Exit" << endl;
      cin >> userChoice;
    } while (userChoice < 1 || userChoice > 5);
    
    /* ...apply the appropriate mass */
    if (userChoice == 1)
      appliedMass += 0.5;
    else if (userChoice == 2)
      appliedMass += 1.0;
    else if (userChoice == 3)
      appliedMass += 2.0;
    else if (userChoice == 4)
      appliedMass += 5.0;

    /* ...try and break the bridge */
    if (userChoice != 5 && score != 0 && mass != 0)
    {
      breakScore = (appliedMass * fabs(mass - joints)) / (mass * score * score);
      cout << "You have a break score of " << breakScore << endl;
    }
  }

  return 0;
}