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

int main()
{
  double d;
  int line;
  string s;
  
  line = 0;
  while(1) {
    cout << "Enter a double: ";
    cout.flush();

    getline(cin, s);
    line++;
    if (cin.eof()) exit(0);
    if (sscanf(s.c_str(), "%lf", &d) != 1) {
      cout << "Line " << line << " Not a double." << endl;
    } else {
      cout << "Double on line " << line << " is " << d << endl;
    }
  }
}