This code for Code Playground is error?Why?

Question

#include <fstream>
#include <iostream>

using namespace std;

int main()
{ ifstream fin("a.csv"); // a.csv = 1,2,3,4,5
if(!fin) {cout<<"my opening error"<<endl; return 1;}
fin.close();
return 0; }

Answer 1

You can't use your own external files in C++ Code Playground.

Answer 2

Mis... I can to write my own files!