file operations

[Kerstin]

Hi,
first of all, that's no homework. I'm doing this kind of stuff at
work! ;-)

I think I managed most of my problems. It's not the best way I
suppose, but it's working. I open the file in r-mode when I need to
read it, close it, and open it again in w-mode to write it, and the
other way round. I tried the w+-mode, but it wasn't working properly
for me.
If anybody knows a better way, please tell me.

bye,
Kerstin