I leave it up to you to investigate why your answer is wrong: File of type is indexed by type....
Do you mean my answer? Let's see:
Assign and
Reset are normal;
Seek() for typed files seeks to the given register and
FileSize() gives the size in registers of the file, so:
Seek(AFile, FileSize(AFile));
will let the file's position at the end of the file so the next write will
append to the file. What's wrong with that?
In case you don't believe it, I've attached a test project.
ETA: In case any doubt arises,
FileSize() is
System.FileSize()