C++ template for I/O from file

template.cpp

#include <bits/stdc++.h>
using namespace std;

#ifdef ENG
string filename = "hash2";
string input_ext = "inp", output_ext = "out", debug_ext = "debugging";
string 	input_filename = filename + '.' + input_ext,
		output_filename = filename + '.' + output_ext,
		debug_filename = filename + '.' + debug_ext;
#endif

main()
{
	#ifdef ENG
	cerr << "Input file :: " << input_filename << endl;
	cerr << "Output file :: " << output_filename << endl;
	cerr << "Debugging file (stderr) :: " << debug_filename << endl;
	if (freopen (input_filename.c_str(), "r", stdin) == nullptr)
		return 	cerr << "No input files found, creating empty input file\n",
				freopen (input_filename.c_str(), "w", stdout), 0;
	freopen (output_filename.c_str(), "w", stdout);
	freopen (debug_filename.c_str(), "w", stderr);
	#endif
}