C++: assign cin to an ifstream variable?

Question

You know the common stdio idiom that stdin is specified by a filename of \"-\", e.g.

if ((strcmp(fname, \"-\"))
    fp = fopen(fname);
else
             


        

Answer 1

• Save the initial streambuf of cin into a variable
• Change the streambuf of cin to the one from the file.
• Do what you need to do
• And don't forget to restore cin streambuf before closing your file -- RAII may help.