Opening file with fstream

Question

I have written a class for handling text files and it looks like this.

#include <fstream>
#include "String.h"

class TextFile
{
    std::fstream stream;

public:
    TextFile(const String& filename)
    {
        stream.open(filename.data(), std::ios::in | std::ios::out);
    std::cout << "File opened " << filename.data() << " " << stream.is_open() << std::endl;
    }

    ~TextFile()
    {
        close();
    }

    template <typename T>
    TextFile& operator<<(const T& data)
    {
        stream << data;
        return *this;
    }

    TextFile& operator<<(const String& s)
    {
        stream << s.data();
        return *this;
    }

    template <typename T>
    TextFile& operator>>(T& data)
    {
        stream >> data;
        return *this;
    }

    void close() 
    {
        if (stream.is_open()) 
            stream.close();
    }
};

I intentionally used fstream and not ifstream or ofstream, because at the time of opening the file, I do not yet know whether I will write to it or read from it. I would then use the TextFile in one of two ways:

TextFile file("somefile.txt")
file << "hello world";
file.close();

TextFile file("somefile.txt")
file >> someString;
file.close();

My issue with this is that it won't open the file, unless it already exists. It only does that if I add std::ios::app to the arguments, but I don't want to append. I want the file to be created, if it doesn't exist, and overwrite its contents if it already does. How do I do this right?