int main(void)  
{
    double sell, earn;
    sell = 0;

    
    while ( sell != -1 )
  {
    printf ("Enter sales in dollars (-1 to end): ");
    scanf ("%lf",&sell);
    if ( sell == -1 )
    {
      break;
    }
    earn = ( sell / 100 * 9 ) + 200;
    printf ("Salary is: $%.2f\n\n",earn);

  }
    
    
  system ("PAUSE");
  return (0);