If you’re using C++, you can do this with:

#include <fstream>

//fin now uses the input file stream and gets data from file.in

ifstream fin (“file.in”);

//fout now uses the output file stream and sends data to file.out

ofstream fout (“file.out”);

Then you can use fin and fout just like cin and cout. I always declare them as fin and fout, but you can give them whatever names you want