std::copy is copying an extra carriage return character

Question

I'm copying the contents of a file, then creating a std::ofstream upon the same file, and then using std::copy with a std::ostream_iterator to that std::ofstream to copy the copied contents back into the file.

My issue is that a new, blank line is getting inserted between each original line.

Here is my code:

std::string firstFile = getFileContents_asString("filepath.txt");
std::ofstream fileOutStream("filepath.txt");
std::ostream_iterator<char> oi(fileOutStream);
std::copy(firstFile.begin(), firstFile.end(), oi);

It takes text like this:

#include "worklogger_pres_model.h"
#include "worklogmodel_container.h"
#include <QSqlRelationalTableModel>

And does this:

#include "worklogger_pres_model.h"

#include "worklogmodel_container.h"

#include <QSqlRelationalTableModel>

In checking out things with a debugger, upon a first debug run, the firstFile string has stretches like this model.h\r\n#includ.

Upon a second debug run, the firstFile string has stretches like this model.h\r\r\n#includ.

Why is std::copy copying an extra \r or carriage return, per each carriage return occurrence, back into the file?

If it turns out to be helpful, here is the getFileContents_asString method.

std::string getFileContents_asString(const char * filename) {
    std::ifstream f (filename, std::ios::in | std::ios::binary);
    if (f) {
        std::string buffer;
        f.seekg(0, std::ios::end);
        buffer.resize(f.tellg());
        f.seekg(0, std::ios::beg);
        f.read(&buffer[0], buffer.size());
        f.close();
        return buffer;
    } else {
        std::cout << "file could not be opened";
        return std::string("failure to open file");
    }
}

Answer 1

Change this:

std::ofstream fileOutStream("filepath.txt");

to this:

std::ofstream fileOutStream("filepath.txt", std::ios::in | std::ios::binary);

You open the input file in binary, so it would make sense to do the same for the output file too.

---

_{As M.M said:}

Another option is to open both files as text (in which case the memory buffer will contain \n instead of \r\n).