Pangrams

program Pangrams;

var
  letters: array of string;
  userString: string;
  stringPos, lettersPos: integer;
  letterRepeat: boolean;

begin
  while true do
    begin
      writeln('Enter a string:');
      readln(userString);
      for stringPos := 1 to length(userString) do
        begin
          if (ord(upcase(userString[stringPos])) >= 65) and (ord(upcase(userString[stringPos])) <= 90) then
            begin
              letterRepeat := false;
              for lettersPos := 0 to length(letters) - 1 do
                begin
                  if upcase(userString[stringPos]) = upcase(letters[lettersPos]) then
                    letterRepeat := true
                end;
              if not letterRepeat then
                begin
                  setlength(letters, length(letters) + 1);
                  letters[length(letters) - 1] := userString[stringPos];
                end;
            end;
        end;
      if length(letters) < 26 then
        writeln('String is not a pangram!')
      else
        writeln('String is a pangram!');
      setlength(letters, 0);
    end;
end.