Câu 4
program bai4;
uses crt;
var a:array[1..1000]of longint;
      n,i:longint;
begin
clrscr;
write(' Nhap so luong phan tu : ');readln(n);
for i:=1 to n do
begin
write(' a[',i,']=');readln(a[i]);
end.
writeln(' Cac phan tu chia het cho 3 la : ');
for i:=1 to n do if a[i] mod 3=0 then write(a[i],' , ');
readln;
end.