#include <iostream>

int main(int argc, char** argv)
{
  int x;

  std::cout << "Enter a number: ";

  void* success = std::cin >> x;

  if ( success )
  {
    std::cout << "Thank you\n";
  }
  else
  {
    std::cout << "That is not a number\n";
  }

  return 0;
}