#include <iostream.h>
#include <iomanip.h>


double total_cost (int burgers, int fries) {

  if (burgers >= fries) {
    // all fries cost only 0.75
    return (burgers * 2.00) + (fries * 0.75);
  }
  // we have more fries than burgers.
  // each burger and fries combination costs #2.75,
  // and each extra fries costs $1.00
  return (burgers * 2.75) + ((fries - burgers) * 1.00);

}


int main () {

  double cost, cost_of_all_orders = 0;
  int burgers, fries, number_of_orders = 0;

  // get this out of the way (all output requires the same options)
  cout << setiosflags (ios::fixed | ios::showpoint) << setprecision(2);

  for (;;) {

    cout << "Enter burgers and fries (any negative terminates): ";
    cin >> burgers >> fries;

    if ((burgers < 0) || (fries < 0)) {
      break;
    }

    cost = total_cost (burgers, fries);
    cout << "The cost is $" << cost << endl;

    cost_of_all_orders += cost;
    number_of_orders++;

  }

  if (number_of_orders != 0) { // play it safe
    cout << "The average order cost is $"
         << cost_of_all_orders / number_of_orders << endl;
  } // else not doing anything is a reasonable action

}