# include <cstdlib>
# include <iostream>

using namespace std;

int main ( )
//
//  SUM_MINUS allows the user to enter a sequence of numbers which
//  are added up by the program, and the result printed.
//
//  The user signals the end of input by giving the special input 
//  value of -1.0.
//
//  Input can be on a single line:  10 20 30 -1
//  or on multiple lines:
//    10
//    20 30
//    -1
//
{
  int n;
  float sum, x;

  cout << "Enter values, end with -1.0\n";

  sum = 0.0;
  n = 0;
  cin >> x;

  while ( x != -1.0 )
  {
//
//  Increase the loop counter.
//
    n = n + 1;

    sum = sum + x;
    cin >> x;
  }
  cout << "Sum of " << n << " numbers is " << sum << "\n";

  return 0;
}