#include <stdio.h>
#include <iostream>
#include <string>
using namespace std;

int main()
{
  double d;
  int dnum;
  string s;
  
  dnum = 1;
  while(1) {
    cout << "Enter a double: ";
    cout.flush();

    cin >> d;
    if (cin.eof()) exit(0);
    if (cin.fail()) {
      cout << "Not a double." << endl;
      cin.clear();
      cin >> s;
    } else {
      cout << "Double number " << dnum << " is " << d << endl;
      dnum++;
    }
  }
}