Code:

var
nnn,nnn1:string[50];
i,d:integer;
begin
nnn1:='nik'; //Sa ovim uporedjujes
nnn:=chr(1);
i:=1; //duzina stringa je jedan
d:=1;
while (true)  do
        begin
        if d < 256
        then
                begin
                nnn[i]:=chr(ord(nnn[i])+1);
                d:=d+1;
                end
        else
                begin
                i:=i+1;
                nnn:=nnn+chr(1);
                nnn[i]:=chr(ord(nnn[i])+1);
                d:=1;
                end;
       if (nnn=nnn1) then break;
end;
ShowMessage(nnn); //pokazes string koji si dobio

end;