Xcode dynamic path

Hello. I'm *very* new to Xcode and I would like to make a simple program that can copy a file from a directory to another one. How can I create a "dynamic" path, possible the same as the Terminal "~/" so that the program does not need to know the computer and/or user name where the the file is located? I'm programming in C++ (though I have no formal or advanced knowledge, I just know the basics).