Dùng đệ quy in ra dãy n bit nhị phân

program chuoi_n_bit;
const max=250;
var
x:array[1..max] of byte;
i:byte;
n:byte;
procedure inketqua;
var i:byte;
begin
for i:=1 to n do
write(x[i]:5);
writeln;
end;
procedure chuoi(i:byte);
var j:byte;
begin
for j:=0 to 1 do
begin
x[i]:=j;
if i=n then inketqua
else chuoi(i+1);
end;
end;
begin
{n la so bit can sinh}
write(`Nhap so bit can sinh: `);
readln(n);
chuoi(1); {luon bat dau tu 1}
readln;
end.