var
i, j, k, m: integer;
f: file of integer;
begin
writeln('Make bin file');
assign(f, 'file.bin');
rewrite(f);
for i := 1 to 15 do
begin
k := random(5) - 2;
write(k:3);
write(f, k)
end;
close(f);
reset(f);
i := 0;
j := 0;
while not eof(f) do
begin
seek(f, i);
read(f, k);
inc(i);
if k >= 0 then
begin
seek(f, j);
write(f, k);
inc(j)
end
end;
seek(f, j);
truncate(f);
close(f);
writeln;
writeln('Output rebuild bin file');
reset(f);
while not eof(f) do
begin
read(f, k);
write(k:3);
end;
readln
end.