// Code derived from Stroustrup's PPP2 book
// § 10.7.2 Separating dialog from function
//  -and beginning on p 363

#include <iostream>
#include <locale>
#include <stdexcept>
#include <string>

using namespace std;

void error(const string s) { throw runtime_error(s); }
void error(const string s1, const string s2) { error(s1 + s2); }

//------------------------------------------------------------------------------

void skip_to_int()
{
  if (cin.fail()) {  // we found something that wasn’t an integer
    cin.clear();     // we’d like to look at the characters

    for (char ch; cin >> ch;) {  // throw away non-digits
      if (isdigit(ch) || ch == '-') {
        cin.unget();  // put the digit back, so that we can read the number
        return;
      }
    }
  }

  error("no input");  // eof or bad; give up
}

int get_int()
{
  int n = 0;

  while (true) {
    if (cin >> n)
      return n;

    cout << "Sorry, that was not a number; please try again\n";

    skip_to_int();
  }
}

int get_int(int low, int high, const string& greeting, const string& sorry)
{
  cout << greeting << ": [" << low << ':' << high << "]\n";

  while (true) {
    int n = get_int();
    if (low <= n && n <= high)
      return n;

    cout << sorry << ": [" << low << ':' << high << "]\n";
  }
}

int main()
try {
  int strength = get_int(1, 10, "enter strength", "Not in range, try again");

  cout << "strength: " << strength << '\n';

  int altitude = get_int(0, 50000, "Please enter altitude in feet",
                         "Not in range, please try again");

  cout << "altitude: " << altitude << "f above sea level\n";

} catch (exception& e) {
  cerr << "error: " << e.what() << '\n';
  return 1;

} catch (...) {
  cerr << "Oops: unknown exception!\n";
  return 2;
}