include <SpreadsheetCell.h>
  
  include <iostream>
  using namespace std;
  
  int main(int argc, char** argv)
  {
    SpreadsheetCell cell1;
    string s1 = cell1; // Works as expected
    double d2 = cell1;
  
    //  double d1 = cell1 + 3.3; // DOES NOT COMPILE IF YOU DEFINE operator double()
  
    return (0);
  }