#include <iostream.h>
#include <fstream.h>
#include <conio.h>


void pause (void)

{ cout << "Hit any key to continue.\n"; getch(); }



// given the name of a file and an array, reads the values in
// the file and stores them in the array.  returns true if the
// operation was sucessfully completed and false otherwise.  sets
// call by reference parameter "values_read" to the number of
// values actually read (posibly zero)
bool read_file (char filename[], int n, // size of array
                double array[], int &values_read) {

  ifstream fin;
  double value;

  fin.open (filename, ios::in);
  if (fin.fail()) { // file could not be opened
    return false;
  }

  values_read = 0; // nothing read in so far
  for (;;) {

    // try and read another value
    fin >> value;;

    if (fin.fail()) {
      // read did not work for some reason
      if (fin.eof()) {
        // read did not work because we've hit the end of the file
        // - everything is fine
        return true;
      } else {
        // read failed for some other reason - we've a problem
        return false;
      }
    }

    if (values_read == n) {
      // the array is already full - we have overflow
      return false;
    }

    // store the value into the array
    array[values_read++] = value;

  }

  // we can never get here (therefore no return is required)

}


double sum_up_elements (double array[], int first, int count)

{
  double sum;
  int i;

  sum = 0;
  for (i = first; i < first + count; i++) {
    sum += array[i];
  }
  return sum;
}


int main (void) {

  const int array_size = 200;
  char filename[60];
  double array [array_size], max_weight, weight;
  int train_cars, first_car, test_cars, problems;

  cout << "Enter name of file: ";
  cin >> filename;

  if (!read_file (filename, array_size, array, train_cars)) {
    cout << "Could not read file.\n";
    pause(); return 0;
  }

  cout << "Enter number of cars and max weight: ";
  cin >> test_cars >> max_weight;

  if (train_cars < test_cars) {
    // a short train - just check that its entire weight is less
    // than the maximum allowable weight
    weight = sum_up_elements(array, 0, train_cars);
    if (weight > max_weight) {
      cout << "The train is short but too heavy (" << weight << " tons).\n";
    } else {
      cout << "No problems detected.\n";
    }
    pause(); return 0;
  }

  problems = 0;
  for (first_car = 0; first_car <= train_cars - test_cars; first_car++) {
    weight = sum_up_elements(array, first_car, test_cars);
    if (weight > max_weight) {
      cout << "Cars " << (first_car + 1) << " through "
           << (first_car + test_cars)
           << " exceed the maximum weight (weight = "
           << weight << " tons).\n";
      problems++;
    }
  }
  cout << "Number of problems detected: " << problems << endl;

  pause();

  return 0;

}