Correction: it's difficult in C and C++, but of course Perl would have a module for it. ;) It looks like a very useful one, too . . . .

You can read from and write to the same file at once, but it's difficult.

You're best off creating a copy of the file and modifying that, then replacing the original file with the modified one, as...

You know that your company's logo isn't a polygon. :)

You can use start to control even more about the notepad window. For instance,
system("start /maximized notepad");
will start notepad maximized.