[Asinkrit]

Код:

...
AssignFile(f1, 'original.dat');
Reset(f1);
AssignFile(f2, 'temp.tmp');
Rewrite(f2);

while not eof(f1) do
    begin
    read(f1,n);
    write(f2,n);
    if n>0 then write(f2, 0);
    end;

CloseFile(f2);
CloseFile(f1);

DeleteFile('original.dat');
Rename(f2, 'original.dat');