Question

I just found a way to copy a file with iterators to another file:

ifstream ifile("file1.txt");
ofstream ofile("file2.txt");
copy(istream_iterator<string>(ifile),
     istream_iterator<string>(),
     ostream_iterator<string>(ofile, " "));

It works, but unfortunately all text from “file1.txt” is in only one line at “file2.txt”, but oryginally at “file1.txt” are many lines.

I tried to change string between iterator’s loop:

copy(istream_iterator<string>(ifile),
     istream_iterator<string>(),
     ostream_iterator<string>(ofile, "\n"));

but result at “file2.txt” is worse – every word is in different line.

My question:
is any way to copy file with iterators but without loosing any informations, or should I do it with getline()?

Answer 1

istream_iterator<T> iter(stream) will use formatted input functions, so that ++iter is somewhat equivalent to:

T t;
stream >> t;

For string objects this means discarding any leading whitespace and reading only until the next whitespace character.

If you want unformatted operations instead, use istreambuf_iterator<char> (as was noted in the comments).