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


void main (void) {

  double interest_rate, loan_amount, payment_amount, graduation_debt,
         debt, total_payments;
  int study_years, payment_years, i;
  const int max_payment_years = 50;

  // we want all floating point ouput in dollars and cents
  cout << setprecision(2) << setiosflags (ios::fixed | ios::showpoint);

  cout << "Enter interest rate (in %, -ve to stop): ";
  cin >> interest_rate;

  while (interest_rate >= 0) {

    cout << "Enter loan and payment amounts: ";
    cin >> loan_amount >> payment_amount;

    // output table header
    cout << endl <<
       " Study Years   Graduation Debt  Payment Years   Total Paid"
       << endl <<
       "-----------------------------------------------------------"
       << endl;

    for (study_years = 4; study_years <= 10; study_years++) {

      // compute debt at graduation
      graduation_debt = 0;
      for (i = 0; i < study_years; i++) {
        graduation_debt = (graduation_debt + loan_amount) *
                          (1.0 + (interest_rate / 100.0));
      }

      // output first part of table line
      cout << setw(6) << study_years << setw(20) << graduation_debt;

      // compute years to pay
      debt = graduation_debt; total_payments = 0; payment_years = 0;
      while ((debt != 0) && (payment_years < max_payment_years)) {
        debt *= (1 + (interest_rate / 100.0));
        if (debt <= payment_amount) {
          total_payments += debt; debt = 0;
        } else {
          total_payments += payment_amount; debt -= payment_amount;
        }
        payment_years++;
      }

      // output second part of table line
      if (debt == 0) { // debt paid off
        cout << setw(15) << payment_years << setw(16) << total_payments << endl;
      } else if (debt < graduation_debt) { // debt is coming down, though slowly
        cout << "       Calcs aborted at " << max_payment_years
             << " years" << endl;
      } else { // the deby will never get paid off
        cout << "       The debt keeps on growing." << endl;
      }

    }

    // the endl leaves a blank line between the table and our prompt message
    cout << endl << "Enter interest rate (in %, -ve to stop): ";
    cin >> interest_rate;

  }

}