Thread: defaulting ifstream variable to standard input

Hi peeps

Can anyone tell me what must be a fairly standard incantation?

About a decade ago I wrote

Code:

    ifstream fin;

    if (NULL == inputStream)
    {
        fin.attach(0);
        inputStream = "stdin";
    }
    else
    {
        fin.open(inputStream, ios::in);
    }

inputStream is NULL unless a filename has been specified on the command line. The attach() function that was available with that compiler allowed me to use this program as part of a pipeline.

Code:

who -a | sortByDate

or

Code:

sortByDate uuu.txt

I haven't really used C++ since then and the attach() function seems to have been an extension that isn't available today. I can't simply do

Code:

fin = cin

can I?