/*
** $Id: sum.cc 824 2008-03-09 19:23:52Z phf $
**
** Silly example for summing a sequence of positive integers
** from standard input.
**
** Also shows pieces of the error handling protocol that can
** be used with the std::cin stream.
*/

#include <iostream>
#include <string>

// just to illustrate how the status changes...
void print_state()
{
  std::cout << "std::cin status: ";
  if (std::cin.eof()) { std::cout << "[EOF]"; }
  if (std::cin.good()) { std::cout << "[GOOD]"; }
  if (std::cin.bad()) { std::cout << "[BAD]"; }
  if (std::cin.fail()) { std::cout << "[FAIL]"; }
  std::cout << std::endl;
}

// and here we go summing those positive integers...
int main()
{
  print_state();

  int sum = 0;
  // can't use the usual while construct since we want
  // to skip input errors; if we use while (cin>>x) we
  // would not only stop the loop on EOF, but also on
  // other error conditions... :-/
  for (;;) {
    int x;
    std::cin >> x; // read an integer

    print_state();

    if (std::cin.eof()) {
      std::cout << "End of file, done!" << std::endl;
      break;
    }

    if (std::cin.good()) {
      if (x > 0) {
        sum += x;
      }
      else {
        std::cout << "Not a positive integer, done!" << std::endl;
        break;
      }
    }
    else {
      std::cout << "You didn't type an integer!" << std::endl;
      std::cin.clear();
      std::string crap;
      std::cin >> crap; // skip whatever it was up to next whitespace
    }
  }
  std::cout << "The sum is " << sum << " I hope..." << std::endl;
}