var
  s:string;
  num,c:integer;
begin
  repeat
    write('Input a number or a character(-1 to end):');readln(s);
    if s='-1' then exit;
    if s[1] in ['a'..'z'] then writeln(ord(s[1])-96)
    else
      begin
        val(s,num,c);
        writeln(chr(num+96));
      end;
  until false;
end.

数组作何用处？