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Latest revision as of 14:38, 10 January 2024

An ordered word is a word in which the letters appear in alphabetic order.

Examples include abbey and dirt.

Task

Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.

(Examples that access the dictionary file locally assume that you have downloaded this file yourself.)

The display needs to be shown on this page.

Related tasks

Other tasks related to string operations:

Metrics

Counting

Remove/replace

Anagrams/Derangements/shuffling

Find/Search/Determine

Formatting

Song lyrics/poems/Mad Libs/phrases

Tokenize

Sequences

11l

Translation of: Python

V words = File(‘unixdict.txt’).read().split("\n")
V ordered = words.filter(word -> word == sorted(word))
V maxlen = max(ordered, key' w -> w.len).len
V maxorderedwords = ordered.filter(word -> word.len == :maxlen)
print(maxorderedwords.join(‘ ’))

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

In find-longest-ordered-words, len, word, and words are used as local variables. open returns an integer as a file-handle. chars returns the number of characters in a symbol's name. eq can be used to compare numbers for equality.

(defun longest-ordered-words ()
  (find-longest-ordered-words
    (open 'notes/unixdict!.txt t)))

(defun find-longest-ordered-words
             (h (len . 0) (word) (words))
  (loop
    (until (eof h)
      (close h)
      words)
    (setq word (readline h))
    (cond ((lessp (chars word) len))
          ((not (ordered-p word)))
          ((eq (chars word) len)
           (setq words (cons word words)))
          (t
           (setq len (chars word))
           (setq words (list word))))))

(defun ordered-p (word)
  (nondecreasing-p
    (mapc ordinal (explode word))))

(defun nondecreasing-p (numbers)
  (or (null numbers)
      (null (cdr numbers))
      (and (not (greaterp (car numbers) (cadr numbers)))
           (nondecreasing-p (cdr numbers)))))

Output:

(longest-ordered-words) will return

(knotty glossy floppy effort
 choppy choosy chilly biopsy
 billow bellow almost accost
 access accept accent abbott)

Action!

In the following solution the input file is loaded from H6 drive. Altirra emulator automatically converts CR/LF character from ASCII into 155 character in ATASCII charset used by Atari 8-bit computer when one from H6-H10 hard drive under DOS 2.5 is used.

CHAR ARRAY line(256)

BYTE FUNC IsOrderedWord(CHAR ARRAY word)
  BYTE len,i

  len=word(0)
  IF len<=1 THEN RETURN (1) FI

  FOR i=1 TO len-1
  DO
    IF word(i)>word(i+1) THEN
      RETURN (0)
    FI
  OD
RETURN (1)

BYTE FUNC FindLongestOrdered(CHAR ARRAY fname)
  BYTE max,dev=[1]

  max=0
  Close(dev)
  Open(dev,fname,4)
  WHILE Eof(dev)=0
  DO
    InputSD(dev,line)
    IF line(0)>max AND IsOrderedWord(line)=1 THEN
      max=line(0)
    FI
  OD
  Close(dev)
RETURN (max)

PROC FindWords(CHAR ARRAY fname BYTE n)
  BYTE count,dev=[1]

  Close(dev)
  Open(dev,fname,4)
  WHILE Eof(dev)=0
  DO
    InputSD(dev,line)
    IF line(0)=n AND IsOrderedWord(line)=1 THEN
      Print(line) Put(32)
    FI
  OD
  Close(dev)
RETURN

PROC Main()
  CHAR ARRAY fname="H6:UNIXDICT.TXT"
  BYTE max

  PrintE("Finding the longest words...")
  PutE()
  max=FindLongestOrdered(fname)

  FindWords(fname,max)
RETURN

Output:

Screenshot from Atari 8-bit computer

Finding the longest words...

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Ada

with Ada.Text_IO, Ada.Containers.Indefinite_Vectors; 
use Ada.Text_IO;

procedure Ordered_Words is
   package Word_Vectors is new Ada.Containers.Indefinite_Vectors
      (Index_Type => Positive, Element_Type => String);
   use Word_Vectors;
   File : File_Type;
   Ordered_Words : Vector;
   Max_Length : Positive := 1;
begin
   Open (File, In_File, "unixdict.txt");
   while not End_Of_File (File) loop
      declare
         Word : String := Get_Line (File);
      begin
         if (for all i in Word'First..Word'Last-1 => Word (i) <= Word(i+1)) then
            if Word'Length > Max_Length then
               Max_Length := Word'Length;
               Ordered_Words.Clear;
               Ordered_Words.Append (Word);
            elsif Word'Length = Max_Length then
               Ordered_Words.Append (Word);
            end if;
         end if;
      end;
   end loop;
   for Word of Ordered_Words loop
     Put_Line (Word);
   end loop;
   Close (File);
end Ordered_Words;

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Aime

integer
ordered(data s)
{
    integer a, c, p;

    a = 1;

    p = -1;
    for (, c in s) {
        if (c < p) {
            a = 0;
            break;
        } else {
            p = c;
        }
    }

    a;
}

integer
main(void)
{
    file f;
    text s;
    index x;

    f.affix("unixdict.txt");

    while (f.line(s) != -1) {
        if (ordered(s)) {
            x.v_list(~s).append(s);
        }
    }

    l_ucall(x.back, o_, 0, "\n");

    return 0;
}

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.3.win32

.

PROC ordered = (STRING s)BOOL:
  BEGIN
    FOR i TO UPB s - 1 DO IF s[i] > s[i+1] THEN return false FI OD;
    TRUE EXIT
    return false: FALSE
  END;

IF FILE input file;
   STRING file name = "unixdict.txt";
   open(input file, file name, stand in channel) /= 0
THEN
  print(("Unable to open file """ + file name + """", newline))
ELSE
  BOOL at eof := FALSE;
  on logical file end (input file, (REF FILE f)BOOL: at eof := TRUE);

  FLEX [1:0] STRING words;
  INT idx := 1;
  INT max length := 0;

  WHILE NOT at eof
  DO
    STRING word;
    get(input file, (word, newline));
    IF UPB word >= max length
    THEN IF ordered(word)
         THEN
           max length := UPB word;
           IF idx > UPB words
           THEN
             [1 : UPB words + 20] STRING tmp;
             tmp[1 : UPB words] := words;
             words := tmp
           FI;
           words[idx] := word;
           idx +:= 1
         FI
    FI
  OD;
  print(("Maximum length of ordered words: ", whole(max length, -4), newline));
  FOR i TO idx-1
  DO
    IF UPB words[i] = max length THEN print((words[i], newline)) FI
  OD
FI

Output:

Maximum length of ordered words:    6
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Amazing Hopper

#include <basico.h>

#define MAX_LINE   30

algoritmo
    
    fd=0
    word={}, result={}
    old_word="",new_word=""
    
    fijar separador (NULO)

    abrir para leer("basica/unixdict.txt",fd)

    iterar mientras ' no es fin de archivo (fd) '
       usando 'MAX_LINE', leer línea desde(fd), 
       ---copiar en 'old_word'---, separar para 'word '
       word, ---retener--- ordenar esto,
       encadenar en 'new_word'

       new_word, meter según (#(old_word == new_word), result)

    reiterar

    cerrar archivo(fd)

    result ---retener---, obtener largo ---retener---
    obtener máximo valor, es mayor o igual?, replicar esto
    compactar esto
    
    fijar separador 'NL', luego imprime todo
    
terminar

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

APL

Works in NARS2000 APL; ("Objects" menu -> New, paste this in, save. Then run in the main session manager).

result←longest_ordered_words file_path

f←file_path ⎕NTIE 0            ⍝ open file
text←⎕NREAD f 'char8'          ⍝ read vector of 8bit chars
⎕NUNTIE f                      ⍝ close file

lines←text⊂⍨~text∊(⎕UCS 10 13) ⍝ split into lines (\r\n)

⍝ filter only words with ordered characters
ordered_words←lines/⍨{(⍳∘≢≡⍋)⍵}¨lines

⍝ find max of word lengths, filter only words with that length
result←ordered_words/⍨lengths=⍨⌈/lengths←≢¨ordered_words

The ordered character filter is a train which uses gradeup to say which order you would have to pick the characters, to put them in order. e.g. ⍋ 'zxy' is 2 3 1 because you'd have to pick the second character, then the third, then the first, to put them in order. If they are in order then the result is the integers 1 2 3 .. to the length of the word.

And it generates the integers up to the length of the word, e.g. 1 2 3. and compares if those two arrays are the same.

Then uses that information as a filter against the original word list.

The result is: lengths of each ordered word, which equal the max-reduce of the list of lengths (longest word), used as a filter against the ordered word list.

Output:

      longest_ordered_words 'd:\unixdict.txt'
abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

AppleScript

use AppleScript version "2.3.1" -- Mac OS 10.9 (Mavericks) or later — for these 'use' commands.
use sorter : script "Insertion sort" -- https://www.rosettacode.org/wiki/Sorting_algorithms/Insertion_sort#AppleScript.
use scripting additions

on longestOrderedWords(wordList)
    script o
        property allWords : wordList
        property orderedWords : {}
    end script
    
    set longestWordLength to 0
    set astid to AppleScript's text item delimiters
    set AppleScript's text item delimiters to ""
    ignoring case
        repeat with i from 1 to (count o's allWords)
            set thisWord to item i of o's allWords
            set thisWordLength to (count thisWord)
            if (thisWordLength ≥ longestWordLength) then
                set theseCharacters to thisWord's characters
                tell sorter to sort(theseCharacters, 1, -1)
                set sortedWord to theseCharacters as text
                if (sortedWord = thisWord) then
                    if (thisWordLength > longestWordLength) then
                        set o's orderedWords to {thisWord}
                        set longestWordLength to thisWordLength
                    else
                        set end of o's orderedWords to thisWord
                    end if
                end if
            end if
        end repeat
    end ignoring
    set AppleScript's text item delimiters to astid
    
    return (o's orderedWords)
end longestOrderedWords

-- Test code:
local wordList
set wordList to paragraphs of (read (((path to desktop as text) & "www.rosettacode.org:unixdict.txt") as alias) as «class utf8»)
-- ignoring white space, punctuation and diacriticals
return longestOrderedWords(wordList)
--- end ignoring

Output:

{"abbott", "accent", "accept", "access", "accost", "almost", "bellow", "billow", "biopsy", "chilly", "choosy", "choppy", "effort", "floppy", "glossy", "knotty"}

Arturo

ordered?: function [w]->
    w = join sort split w

words: read.lines relative "unixdict.txt"
ret: new []
loop words 'wrd [
    if ordered? wrd ->
        'ret ++ #[w: wrd l: size wrd]
]

sort.descending.by: 'l 'ret
maxl: get first ret 'l
print sort map select ret 'x -> maxl = x\l
                          'x -> x\w

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

AutoHotkey

This script uses the ASCII value of each letter to determine its place in the alphabet. Given a dictionary not all in the same case, StringLower could be used. This script assumes a locally downloaded copy of the dictionary, but UrlDownloadToFile could be used. The purpose of the GUI is simply to display a field where the user can copy the list. MsgBox could be used, or FileAppend.

MaxLen=0
Loop, Read, UnixDict.txt         ; Assigns A_LoopReadLine to each line of the file
{
    thisword := A_LoopReadLine   ; Just for readability
    blSort := isSorted(thisWord) ; reduce calls to IsSorted to improve performance
    ThisLen := StrLen(ThisWord)  ; reduce calls to StrLen to improve performance
    If (blSort = true and ThisLen = maxlen)
        list .= ", " . thisword
    Else If (blSort = true and ThisLen > maxlen)
    {
        list := thisword
        maxlen := ThisLen
    }
}

IsSorted(word){  ; This function uses the ASCII value of the letter to determine its place in the alphabet.
                           ;        Thankfully, the dictionary is in all lowercase
    lastchar=0
    Loop, parse, word
    {
        if ( Asc(A_LoopField) < lastchar )
            return false
        lastchar := Asc(A_loopField)
    }
    return true
}

GUI, Add, Edit, w300 ReadOnly, %list%
GUI, Show
return ; End Auto-Execute Section

GUIClose:
ExitApp

Output:

abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty

AWK

BEGIN {
	abc = "abcdefghijklmnopqrstuvwxyz"
}

{
	# Check if this line is an ordered word.
	ordered = 1  # true
	left = -1
	for (i = 1; i <= length($0); i++) {
		right = index(abc, substr($0, i, 1))
		if (right == 0 || left > right) {
			ordered = 0  # false
			break
		}
		left = right
	}

	if (ordered) {
		score = length($0)
		if (score > best["score"]) {
			# Reset the list of best ordered words.
			best["score"] = score
			best["count"] = 1
			best[1] = $0
		} else if (score == best["score"]) {
			# Add this word to the list.
			best[++best["count"]] = $0
		}
	}
}

END {
	# Print the list of best ordered words.
	for (i = 1; i <= best["count"]; i++)
		print best[i]
}

You must provide unixdict.txt as input.

$ awk -f ordered-words.awk unixdict.txt                                        
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

BaCon

'Ordered words - improved version
OPTION COLLAPSE TRUE

list$ = LOAD$("unixdict.txt")

FOR word$ IN list$ STEP NL$

    term$ = EXTRACT$(SORT$(EXPLODE$(word$, 1)), " ")

    IF word$ = term$ THEN
        IF LEN(term$) > MaxLen THEN
            MaxLen = LEN(term$)
            result$ = word$
        ELIF LEN(term$) = MaxLen THEN
            result$ = APPEND$(result$, 0, word$, NL$)
        END IF
    END IF
NEXT

PRINT result$

Output:

prompt$ bacon ordered-words
Converting 'ordered-words.bac'... done, 29 lines were processed in 0.004 seconds.
Compiling 'ordered-words.bac'... cc  -c ordered-words.bac.c
cc -o ordered-words ordered-words.bac.o -lbacon -lm
Done, program 'ordered-words' ready.
prompt$ ./ordered-words
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

BBC BASIC

An optimisation is that the word isn't checked for being ordered unless it is at least as long as the current maximum.

      dict% = OPENIN("unixdict.txt")
      IF dict%=0 ERROR 100, "Failed to open dictionary file"
      
      max% = 2
      REPEAT
        A$ = GET$#dict%
        IF LENA$ >= max% THEN
          i% = 0
          REPEAT i% += 1
          UNTIL ASCMID$(A$,i%) > ASCMID$(A$,i%+1)
          IF i% = LENA$ THEN
            IF i% > max% max% = i% : list$ = ""
            list$ += A$ + CHR$13 + CHR$10
          ENDIF
        ENDIF
      UNTIL EOF#dict%
      CLOSE #dict%
      PRINT list$
      END

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Befunge

The word list is read from stdin, so ideally requires an interpreter that can accept input redirected from a file. It's still possible to enter the test data manually, though - you would just need to mark the end of the list with a blank line.

Memory usage isn't very efficient - the matching list is stored one word per line - so on a standard Befunge-93 interpreter there is an upper limit of 22 matches. This is not a problem for the unix dictionary, which only requires 16, but it's theoretically possible that other data sets could run out of space.

00p30p>_010p120p0>#v0~>>\$::48*\`\"~"`+!>>#v_$:#v_>30g:!#v_1-30p55+0>:30g3+g\1v
>0#v _$^#::\p04:<^+>#1^#\p01:p02*g02!`\g01:<@$ _ ,#!>#:<$<^<!:g03$<_^#!`\g00:+<
^<o>\30g2+p40g1+^0p00p03+1*g03!-g00 < < < < < <:>#$:#$00g#<\#<`#<!#<2#$0g#<*#<_

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

BQN

(↕∘≠≡⍋) checks for an ordered word.

¯1⊑(≠¨⊔⊢) groups by length, and takes the last (longest length) group.

   words←•FLines "unixdict.txt"
   ¯1⊑(≠¨⊔⊢)(↕∘≠≡⍋)¨⊸/words
⟨ "abbott" "accent" "accept" "access" "accost" "almost" "bellow" "billow" "biopsy" "chilly" "choosy" "choppy" "effort" "floppy" "glossy" "knotty" ⟩

Bracmat

  ( orderedWords
  =   bow result longestLength word character
    .     0:?bow
        & :?result
        & 0:?longestLength
        & @( get$(!arg,STR)
           :   ?
               ( [!bow %?word \n [?bow ?
               & @( !word
                  : ( ? %@?character <%@!character ?
                    |   ?
                        (   [!longestLength
                          & !word !result:?result
                        |   [>!longestLength:[?longestLength
                          & !word:?result
                        | 
                        )
                    )
                  )
               & ~`
               )
           )
      | !result
  )
& orderedWords$"unixdict.txt"

  knotty
  glossy
  floppy
  effort
  choppy
  choosy
  chilly
  biopsy
  billow
  bellow
  almost
  accost
  access
  accept
  accent
  abbott

Burlesque

ln{so}f[^^{L[}>mL[bx(==)[+(L[)+]f[uN

Output:

$ ./burlesque --file ordered_words.brl < unixdict.txt 
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

C

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>


#define MAXLEN 100
typedef char TWord[MAXLEN];


typedef struct Node {
    TWord word;
    struct Node *next;
} Node;


int is_ordered_word(const TWord word) {
    assert(word != NULL);
    int i;

    for (i = 0; word[i] != '\0'; i++)
        if (word[i] > word[i + 1] && word[i + 1] != '\0')
            return 0;

    return 1;
}


Node* list_prepend(Node* words_list, const TWord new_word) {
    assert(new_word != NULL);
    Node *new_node = malloc(sizeof(Node));
    if (new_node == NULL)
        exit(EXIT_FAILURE);

    strcpy(new_node->word, new_word);
    new_node->next = words_list;
    return new_node;
}


Node* list_destroy(Node *words_list) {
    while (words_list != NULL) {
        Node *temp = words_list;
        words_list = words_list->next;
        free(temp);
    }

    return words_list;
}


void list_print(Node *words_list) {
    while (words_list != NULL) {
        printf("\n%s", words_list->word);
        words_list = words_list->next;
    }
}


int main() {
    FILE *fp = fopen("unixdict.txt", "r");
    if (fp == NULL)
        return EXIT_FAILURE;

    Node *words = NULL;
    TWord line;
    unsigned int max_len = 0;

    while (fscanf(fp, "%99s\n", line) != EOF) {
        if (strlen(line) > max_len && is_ordered_word(line)) {
            max_len = strlen(line);
            words = list_destroy(words);
            words = list_prepend(words, line);
        } else if (strlen(line) == max_len && is_ordered_word(line)) {
            words = list_prepend(words, line);
        }
    }

    fclose(fp);
    list_print(words);

    return EXIT_SUCCESS;
}

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Alternative version with dynamic array:

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>


#define MAXLEN 100
typedef char TWord[MAXLEN];


typedef struct WordsArray {
    TWord *words;
    size_t len;
} WordsArray;


int is_ordered_word(const TWord word) {
    assert(word != NULL);
    int i;

    for (i = 0; word[i] != '\0'; i++)
        if (word[i] > word[i + 1] && word[i + 1] != '\0')
            return 0;

    return 1;
}


void array_append(WordsArray *words_array, const TWord new_word) {
    assert(words_array != NULL);
    assert(new_word != NULL);
    assert((words_array->len == 0) == (words_array->words == NULL));

    words_array->len++;
    words_array->words = realloc(words_array->words,
                                 words_array->len * sizeof(words_array->words[0]));
    if (words_array->words == NULL)
        exit(EXIT_FAILURE);
    strcpy(words_array->words[words_array->len-1], new_word);
}


void array_free(WordsArray *words_array) {
    assert(words_array != NULL);
    free(words_array->words);
    words_array->words = NULL;
    words_array->len = 0;
}


void list_print(WordsArray *words_array) {
    assert(words_array != NULL);
    size_t i;
    for (i = 0; i < words_array->len; i++)
        printf("\n%s", words_array->words[i]);
}


int main() {
    FILE *fp = fopen("unixdict.txt", "r");
    if (fp == NULL)
        return EXIT_FAILURE;

    WordsArray words;
    words.len = 0;
    words.words = NULL;

    TWord line;
    line[0] = '\0';
    unsigned int max_len = 0;

    while (fscanf(fp, "%99s\n", line) != EOF) { // 99 = MAXLEN - 1
        if (strlen(line) > max_len && is_ordered_word(line)) {
            max_len = strlen(line);
            array_free(&words);
            array_append(&words, line);
        } else if (strlen(line) == max_len && is_ordered_word(line)) {
            array_append(&words, line);
        }
    }

    fclose(fp);
    list_print(&words);
    array_free(&words);

    return EXIT_SUCCESS;
}

Mmap

Shorter and potentially much faster version with mmap (2). No stinky malloc or scanf calls.

#include <stdio.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <err.h>
#include <string.h>

int ordered(char *s, char **end)
{
	int r = 1;
	while (*++s != '\n' && *s != '\r' && *s != '\0')
		if (s[0] < s[-1]) r = 0;

	*end = s;
	return r;
}

int main()
{
	char *buf, *word, *end, *tail;
	struct stat st;
	int longest = 0, len, fd;

	if ((fd = open("unixdict.txt", O_RDONLY)) == -1) err(1, "read error");

	fstat(fd, &st);
	if (!(buf = mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)))
		err(1, "mmap");

	for (word = end = buf; end < buf + st.st_size; word = end) {
		while (*word == '\r' || *word == '\n') word++;
		if (!ordered(word, &end)) continue;
		if ((len = end - word + 1) < longest) continue;
		if (len > longest) {
			tail = buf;  /* longer words found; reset out buffer */
			longest = len;
		}
		/* use the same mmap'd region to store output.  because of MAP_PRIVATE,
		 * change will not go back to file.  mmap is copy on write, and we are using
		 * only the head space to store output, so kernel doesn't need to copy more
		 * than the words we saved--in this case, one page tops.
		 */
		memcpy(tail, word, len);
		tail += len;
		*tail = '\0';
	}
	printf(buf);

	munmap(buf, st.st_size);
	close(fd);
	return 0;
}

C#

using System;
using System.Linq;
using System.Net;

static class Program
{
    static void Main(string[] args)
    {
        WebClient client = new WebClient();
        string text = client.DownloadString("http://www.puzzlers.org/pub/wordlists/unixdict.txt");
        string[] words = text.Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);

        var query = from w in words
                    where IsOrderedWord(w)
                    group w by w.Length into ows
                    orderby ows.Key descending
                    select ows;

        Console.WriteLine(string.Join(", ", query.First().ToArray()));
    }

    private static bool IsOrderedWord(string w)
    {
        for (int i = 1; i < w.Length; i++)
            if (w[i] < w[i - 1])
                return false;

        return true;
    }
}

Output:

abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty

C++

#include <algorithm>
#include <fstream>
#include <iostream>
#include <iterator>
#include <string>
#include <vector>

bool ordered(const std::string &word)
{
    return std::is_sorted(word.begin(), word.end()); // C++11
}

int main()
{
    std::ifstream infile("unixdict.txt");
    if (!infile) {
        std::cerr << "Can't open word file\n";
        return -1;
    }

    std::vector<std::string> words;
    std::string word;
    int longest = 0;

    while (std::getline(infile, word)) {
        int length = word.length();
        if (length < longest) continue; // don't test short words
        
        if (ordered(word)) {
            if (longest < length) {
                longest = length; // set new minimum length
                words.clear(); // reset the container
            }
            words.push_back(word);
        }
    }
    std::copy(words.begin(), words.end(), std::ostream_iterator<std::string>(std::cout, "\n"));
}

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Clojure

(defn is-sorted? [coll]
  (not-any? pos? (map compare coll (next coll))))

(defn take-while-eqcount [coll]
  (let [n (count (first coll))]
    (take-while #(== n (count %)) coll)))

(with-open [rdr (clojure.java.io/reader "unixdict.txt")]
  (->> rdr
       line-seq
       (filter is-sorted?)
       (sort-by count >)
       take-while-eqcount
       (clojure.string/join ", ")
       println))

Output

abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty

CLU

is_ordered = proc (s: string) returns (bool)
    last: char := '\000'
    for c: char in string$chars(s) do
        if last > c then return(false) end
        last := c
    end
    return(true)
end is_ordered

lines = iter (s: stream) yields (string)
    while true do 
        yield(stream$getl(s))
        except when end_of_file: break end
    end
end lines

ordered_words = proc (s: stream) returns (array[string])
    words: array[string]
    max_len: int := 0
    for word: string in lines(s) do
        if is_ordered(word) then
            len: int := string$size(word)
            if len > max_len then
                max_len := len
                words := array[string]$[]
            elseif len = max_len then
                array[string]$addh(words,word)
            end
        end
    end
    return(words)
end ordered_words

start_up = proc ()
    dict: stream := stream$open(file_name$parse("unixdict.txt"), "read")
    words: array[string] := ordered_words(dict)
    stream$close(dict)
    
    po: stream := stream$primary_output()
    for word: string in array[string]$elements(words) do
        stream$putl(po, word)
    end
end start_up

Output:

accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

COBOL

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ABC-WORDS.
       
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT DICT ASSIGN TO DISK
           ORGANIZATION LINE SEQUENTIAL.
           
       DATA DIVISION.
       FILE SECTION.
       FD DICT 
           LABEL RECORD STANDARD
           VALUE OF FILE-ID IS "unixdict.txt".
       01 ENTRY.
          03 WORD         PIC X(32).
          03 LETTERS      PIC X OCCURS 32 TIMES, REDEFINES WORD.
       
       WORKING-STORAGE SECTION.
       01 LEN             PIC 99.
       01 MAXLEN          PIC 99 VALUE 0.
       01 I               PIC 99.
       01 OK-FLAG         PIC X.
          88 OK           VALUE '*'.
       
       PROCEDURE DIVISION.
       BEGIN.
           OPEN INPUT DICT.
           
       FIND-LONGEST-WORD.
           READ DICT, AT END CLOSE DICT, GO TO PRINT-LONGEST-WORDS.
           PERFORM CHECK-WORD.
           GO TO FIND-LONGEST-WORD.
           
       PRINT-LONGEST-WORDS.
           ALTER VALID-WORD TO PROCEED TO SHOW-WORD.
           OPEN INPUT DICT.
       
       READ-WORDS.
           READ DICT, AT END CLOSE DICT, STOP RUN.
           PERFORM CHECK-WORD.
           GO TO READ-WORDS.
           
       CHECK-WORD.
           MOVE ZERO TO LEN.
           INSPECT WORD TALLYING LEN 
               FOR CHARACTERS BEFORE INITIAL SPACE.
           MOVE '*' TO OK-FLAG.
           PERFORM CHECK-CHAR-PAIR VARYING I FROM 2 BY 1
               UNTIL NOT OK OR I IS GREATER THAN LEN.
           IF OK, PERFORM DO-WORD.
       
       CHECK-CHAR-PAIR.
           IF LETTERS(I - 1) IS GREATER THAN LETTERS(I), 
               MOVE SPACE TO OK-FLAG.
         
       DO-WORD SECTION.         
       VALID-WORD.
           GO TO CHECK-LENGTH.
       CHECK-LENGTH.
           IF LEN IS GREATER THAN MAXLEN, MOVE LEN TO MAXLEN.
           GO TO DONE.
       SHOW-WORD.
           IF LEN IS EQUAL TO MAXLEN, DISPLAY WORD.
       DONE.
           EXIT.

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

CoffeeScript

ordered_word = (word) ->
  for i in [0...word.length - 1]
    return false unless word[i] <= word[i+1]
  true

show_longest_ordered_words = (candidates, dict_file_name) ->
  words = ['']
  for word in candidates
    continue if word.length < words[0].length
    if ordered_word word
      words = [] if word.length > words[0].length
      words.push word
  return if words[0] == '' # we came up empty
  console.log "Longest Ordered Words (source=#{dict_file_name}):"
  for word in words
    console.log word

dict_file_name = 'unixdict.txt'
file_content = require('fs').readFileSync dict_file_name
dict_words = file_content.toString().split '\n'
show_longest_ordered_words dict_words, dict_file_name

output

> coffee ordered_words.coffee 
Longest Ordered Words (source=unixdict.txt):
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Common Lisp

(defun orderedp (word)
  (reduce (lambda (prev curr)
            (when (char> prev curr) (return-from orderedp nil))
            curr)
          word)
  t)

(defun longest-ordered-words (filename)
  (let ((result nil))
    (with-open-file (s filename)
      (loop
         with greatest-length = 0
         for word = (read-line s nil)
         until (null word)
         do (let ((length (length word)))
              (when (and (>= length greatest-length)
                         (orderedp word))
                (when (> length greatest-length)
                  (setf greatest-length length
                        result nil))
                (push word result)))))
    (nreverse result)))

CL-USER> (longest-ordered-words "unixdict.txt")
("abbott" "accent" "accept" "access" "accost" "almost" "bellow" "billow"
 "biopsy" "chilly" "choosy" "choppy" "effort" "floppy" "glossy" "knotty")

Or in a more functional way:

(defun orderedp (word)
  (apply #'char<= (coerce word 'list)))

(let* ((words (uiop:read-file-lines "unixdict.txt"))
	   (ordered (delete-if-not #'orderedp words))
	   (maxlen (apply #'max (mapcar #'length ordered)))
	   (result (delete-if-not (lambda (l) (= l maxlen)) ordered :key #'length)))
  (format t "~{~A~^, ~}" result))

Output:

abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty

Cowgol

Because Cowgol is meant to run on small systems, this program does not store the words in memory. Instead, it scans through the file twice; once to find the maximum length of the ordered words it finds, and once to actually print the words.

include "cowgol.coh";
include "strings.coh";
include "file.coh";

var filename: [uint8] := "unixdict.txt";
        
# Call a subroutine for every line in a file
interface LineCb(line: [uint8]);
sub ForEachLine(fcb: [FCB], fn: LineCb) is
    var linebuf: uint8[256];
    var bufptr := &linebuf[0];
    
    var len := FCBExt(fcb); # get length of file
    FCBSeek(fcb, 0); # start at beginning of file
    
    while len > 0 loop
        var ch := FCBGetChar(fcb);
        if ch == '\n' then
            # end of line, terminate string
            [bufptr] := 0;
            fn(&linebuf[0]);
            bufptr := &linebuf[0];
        else
            # add char to buffer
            [bufptr] := ch;
            bufptr := @next bufptr;
        end if;
        len := len - 1;
    end loop;
    
    # If the file doesn't cleanly end on a line terminator,
    # also call for last incomplete line
    if ch != '\n' then
        [bufptr] := 0;
        fn(&linebuf[0]);
    end if;
end sub;

# Check if the letters in a word appear in alphabetical order
sub isOrdered(word: [uint8]): (r: uint8) is
    var cr := [word];
    word := @next word;
    loop
        var cl := cr;
        cr := [word];
        word := @next word;
        if cr < 32 then
            r := 1;
            return;
        elseif (cl | 32) > (cr | 32) then
            r := 0;
            return;
        end if;
    end loop;
end sub;

# Find maximum length of ordered words
var maxLen: uint8 := 0;
sub MaxOrderedLength implements LineCb is
    var len := StrLen(line) as uint8;
    if maxLen < len and isOrdered(line) != 0 then
        maxLen := len;
    end if;
end sub;

# Print all ordered words matching maximum length
sub PrintMaxLenWord implements LineCb is
    if maxLen == StrLen(line) as uint8 and isOrdered(line) != 0 then
        print(line);
        print_nl();
    end if;
end sub;

var fcb: FCB;
if FCBOpenIn(&fcb, filename) != 0 then
    print("cannot open unixdict.txt\n");
    ExitWithError();
end if;

ForEachLine(&fcb, MaxOrderedLength);
ForEachLine(&fcb, PrintMaxLenWord);

var foo := FCBClose(&fcb);

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

D

Simple Procedural Version

void main() {
    import std.stdio, std.algorithm, std.range, std.string;

    string[] result;
    size_t maxLen;

    foreach (string word; "unixdict.txt".File.lines) {
        word = word.chomp;
        immutable len = word.walkLength;
        if (len < maxLen || !word.isSorted)
            continue;
        if (len > maxLen) {
            result = [word];
            maxLen = len;
        } else
            result ~= word;
    }

    writefln("%-(%s\n%)", result);
}

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Faster Procedural Version

Faster, same output.

void main() {
    import std.stdio, std.algorithm, std.file, std.range;

    string[] result;
    size_t maxWalkLen;

    foreach (word; "unixdict.txt".readText.splitter) {
        if (word.length >= maxWalkLen && word.isSorted) {
            immutable wlen = word.walkLength;
            if (wlen > maxWalkLen) {
                result.length = 0;
                maxWalkLen = wlen;
            }
            result ~= word.idup;
        }
    }

    writefln("%-(%s\n%)", result);
}

Functional Version

Shorter, same output.

void main() {
    import std.stdio, std.algorithm, std.range, std.file, std.string;

    auto words = "unixdict.txt".readText.split.filter!isSorted;
    immutable maxLen = words.map!q{a.length}.reduce!max;
    writefln("%-(%s\n%)", words.filter!(w => w.length == maxLen));
}

Fastest Memory Mapped Version

Lower level, much faster with large input files (about as fast as the memory mapped C version). The output is the same. It works only with ASCII texts, but unlike the C entry this is portable.

Translation of: C

import std.stdio, core.stdc.string, std.mmfile, std.algorithm;

const(char)[] findWord(const char[] s) pure nothrow @safe @nogc {
    size_t wordEnd = 0;
    while (wordEnd < s.length && s[wordEnd] != '\n' && s[wordEnd] != '\r')
        wordEnd++;
    return s[0 .. wordEnd];
}

void main() {
    auto mmf = new MmFile("unixdict.txt", MmFile.Mode.readCopyOnWrite, 0, null);
    auto txt = cast(char[])(mmf[]);
    size_t maxLen = 0, outStart = 0;

    for (size_t wordStart = 0; wordStart < txt.length; ) {
        while (wordStart < txt.length &&
               (txt[wordStart] == '\r' || txt[wordStart] == '\n'))
            wordStart++;
        const word = findWord(txt[wordStart .. $]);
        wordStart += word.length;

        if (word.length < maxLen || !word.isSorted)
            continue;
        if (word.length > maxLen) {
            // Longer ordered word found, reset the out buffer.
            outStart = 0;
            maxLen = word.length;
        }

        // Use the same mmap'd region to store output. Because of
        // Mode.readCopyOnWrite, change will not go back to file.
        // We are using  only the head space to store output, so
        // kernel doesn't need to copy more than the words we saved,
        // in this case, one page tops.
        memcpy(&txt[outStart], word.ptr, word.length);
        outStart += word.length;
        txt[outStart++] = '\n'; // Words separator in out buffer.
    }

    txt[0 .. outStart].write;
}

Delphi

program POrderedWords;

{$APPTYPE CONSOLE}

uses
  SysUtils, Classes, IdHTTP;

function IsOrdered(const s:string): Boolean;
var
  I: Integer;
begin
  Result := Length(s)<2; // empty or 1 char strings are ordered
  for I := 2 to Length(s) do
    if s[I]<s[I-1] then // can improve using case/localization to order...
      Exit;
  Result := True;
end;

function ProcessDictionary(const AUrl: string): string;
var
  slInput: TStringList;
  I, WordSize: Integer;
begin
  slInput := TStringList.Create;
  try
    with TIdHTTP.Create(nil) do try
      slInput.Text := Get(AUrl);
    finally
      Free;
    end;
    // or use slInput.LoadFromFile('yourfilename') to load from a local file
    WordSize :=0;
    for I := 0 to slInput.Count-1 do begin
      if IsOrdered(slInput[I]) then
        if (Length(slInput[I]) = WordSize) then
          Result := Result + slInput[I] + ' '
        else if (Length(slInput[I]) > WordSize) then begin
          Result := slInput[I] + ' ';
          WordSize := Length(slInput[I]);
        end;
    end;
  finally
    slInput.Free;
  end;
end;

begin
  try
    WriteLn(ProcessDictionary('http://www.puzzlers.org/pub/wordlists/unixdict.txt'));
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.

Output: dictionary directly processed from the URL

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Draco

\util.g

proc nonrec is_ordered(*char str) bool:
    while str* /= '\e' and str* <= (str+1)* do
        str := str + 1
    od;
    str* = '\e' or (str+1)* = '\e'
corp

proc nonrec main() void:
    [64]char buf;
    *char str;
    word length, max_length;
    file(1024) dictfile;
    channel input text dict;
    
    str := &buf[0];
    max_length := 0;
    open(dict, dictfile, "unixdict.txt");
    while readln(dict; str) do
        if is_ordered(str) then
            length := CharsLen(str);
            if length > max_length then max_length := length fi
        fi
    od;
    close(dict);
    
    open(dict, dictfile, "unixdict.txt");
    while readln(dict; str) do
        if is_ordered(str) then
            length := CharsLen(str);
            if length = max_length then writeln(str) fi
        fi
    od;
    close(dict)
corp

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

E

Translation of: Python

pragma.enable("accumulator")

def words := <http://www.puzzlers.org/pub/wordlists/unixdict.txt>.getText().split("\n")
def ordered := accum [] for word ? (word.sort() <=> word) in words { _.with(word) }
def maxLen := accum 0 for word in ordered { _.max(word.size()) }
def maxOrderedWords := accum [] for word ? (word.size() <=> maxLen) in ordered { _.with(word) }
println(" ".rjoin(maxOrderedWords))

One-pass procedural algorithm which avoids keeping the entire data set in memory:

def best := [].diverge()
for `@word$\n` ? (word.sort() <=> word) in <http://www.puzzlers.org/pub/wordlists/unixdict.txt> {
  if (best.size() == 0) {
    best.push(word)
  } else if (word.size() > best[0].size()) {
    best(0) := [word] # replace all
  } else if (word.size() <=> best[0].size()) {
    best.push(word)
  }
}
println(" ".rjoin(best.snapshot()))

Output: abbott accent accept access accost almost bellow billow biopsy chilly choosy

choppy effort floppy glossy knotty

EchoLisp

(define (ordered? str)
  (for/and ([i (in-range 1 (string-length str))])
    (string-ci<=? (string-ref str (1- i)) (string-ref str i))))

(define (ordre words)
(define wl 0)
(define s 's)
	(for/fold (len 0) ((w words))
		(set! wl (string-length w))
		#:continue (< wl len)
		#:when (ordered? w)
		#:continue (and (= len wl) (push s w))
		(push (stack s) w) ;; start a new list of length wl
		wl)
	(stack->list s))
	
;; output
(load 'unixdict)
(ordre (text-parse unixdict))
   → (abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty)

;; with the dictionaries provided with EchoLisp
;; french
  → (accentué) ;; ordered, longest, and ... self-reference
;; english
  → (Adelops alloquy beefily begorry billowy egilops)

Elixir

File.read!("unixdict.txt")
|> String.split
|> Enum.filter(fn word -> String.codepoints(word) |> Enum.sort |> Enum.join == word end)
|> Enum.group_by(fn word -> String.length(word) end)
|> Enum.max_by(fn {length,_words} -> length end)
|> elem(1)
|> Enum.sort
|> Enum.each(fn word -> IO.puts word end)

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Erlang

-module( ordered_words ).

-export( [is_ordered/1, task/0] ).

is_ordered( Word ) -> lists:sort( Word ) =:=  Word.

task() ->
    ok = find_unimplemented_tasks:init_http(),
    Ordered_words = [X || X <- words(), is_ordered(X)],
    Sorted_longest_length_first = lists:reverse( sort_with_length( Ordered_words ) ),
    [{Max_length, _Word1} | _T] = Sorted_longest_length_first,
    Longest_length_first = lists:takewhile( fun({Length, _Word2}) -> Length =:= Max_length end, Sorted_longest_length_first ),
    [X || {_Length, X} <- Longest_length_first].



sort_with_length( Words ) ->
    Words_with_length_first = [{erlang:length(X), X} || X <- Words],
    lists:sort( Words_with_length_first ).

words() -> anagrams_deranged:words_from_url( "http://www.puzzlers.org/pub/wordlists/unixdict.txt" ).

Output:

2> ordered_words:task().
["knotty","glossy","floppy","effort","choppy","choosy",
 "chilly","biopsy","billow","bellow","almost","accost",
 "access","accept","accent","abbott"]

Euphoria

include misc.e

type ordered(sequence s)
    for i = 1 to length(s)-1 do
        -- assume all items in the sequence are atoms
        if s[i]>s[i+1] then
            return 0
        end if
    end for
    return 1
end type

integer maxlen
sequence words
object word
constant fn = open("unixdict.txt","r")
maxlen = -1

while 1 do
    word = gets(fn)
    if atom(word) then
        exit
    end if
    word = word[1..$-1] -- truncate new-line
    if length(word) >= maxlen and ordered(word) then
        if length(word) > maxlen then
            maxlen = length(word)
            words = {}
        end if
        words = append(words,word)
    end if
end while

close(fn)

pretty_print(1,words,{2})

Output:

{
  "abbott",
  "accent",
  "accept",
  "access",
  "accost",
  "almost",
  "bellow",
  "billow",
  "biopsy",
  "chilly",
  "choosy",
  "choppy",
  "effort",
  "floppy",
  "glossy",
  "knotty"
}

F#

open System
open System.IO
 
let longestOrderedWords() =
    let isOrdered = Seq.pairwise >> Seq.forall (fun (a,b) -> a <= b)

    File.ReadLines("unixdict.txt")
    |> Seq.filter isOrdered
    |> Seq.groupBy (fun s -> s.Length)
    |> Seq.sortBy (fst >> (~-))
    |> Seq.head |> snd

longestOrderedWords() |> Seq.iter (printfn "%s")

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Factor

USING: grouping http.client io io.encodings.utf8 io.files
io.files.temp kernel math memoize sequences sequences.extras
unicode.case urls ;
IN: rosetta-code.ordered-words

MEMO: word-list ( -- seq )
    "unixdict.txt" temp-file dup exists? [
        URL" http://puzzlers.org/pub/wordlists/unixdict.txt"
        over download-to
    ] unless utf8 file-lines ;

: ordered-word? ( word -- ? )
    >lower [ <= ] monotonic? ;

: ordered-words-main ( -- )
    word-list [ ordered-word? ] filter
    all-longest [ print ] each ;

Output:

( scratchpad ) USING: ordered-words-main ;
( scratchpad ) main
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Fantom

class Main
{
  public static Bool ordered (Str word)
  {
    word.chars.all |Int c, Int i -> Bool|
    {
      (i == (word.size-1) || c <= word.chars[i+1])
    }
  }

  public static Void main ()
  {
    Str[] words := [,]
    File(`unixdict.txt`).eachLine |Str word|
    {
      if (ordered(word))
      {
        if (words.isEmpty || words.first.size < word.size)
        { // reset the list
          words = [word]
        } 
        else if (words.size >= 1 && words.first.size == word.size)
        { // add word to existing ones
          words.add (word)
        }
      }
    }
    echo (words.join (" "))
  }
}

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

FBSL

Downloads the list from puzzlers.org.

#APPTYPE CONSOLE

FUNCTION RESTfulGET(url)
    DIM %HTTP = CREATEOBJECT("WinHttp.WinHttpRequest.5.1")
    CALLMETHOD(HTTP, ".open %s, %s, %d", "GET", url, FALSE)
    CALLMETHOD(HTTP, ".send")
    RETURN GETVALUE("%s", HTTP, ".ResponseText")
END FUNCTION

DIM $TEXT = RESTfulGET("http://www.puzzlers.org/pub/wordlists/unixdict.txt")
DIM dict[] = Split(TEXT, CHR(10))
DIM max AS INTEGER = UBOUND(dict)
DIM theword AS STRING
DIM words[]
FOR DIM i = 0 TO max
    theWord = dict[i]
    IF isOrdered(theWord) THEN
        words[LEN(theWord)] = words[LEN(theWord)] & " " & theWord
    END IF
NEXT

PRINT words[UBOUND(words)]

PAUSE

FUNCTION isOrdered(s)
    FOR DIM i = 1 TO LEN(s) - 1
        IF s{i} > s{i + 1} THEN
            RETURN FALSE
        END IF
    NEXT
    RETURN TRUE
END FUNCTION

Output

 abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Press any key to continue...

Forth

Works with: 4tH version 3.61.2

This program uses a string stack, which means that all matching words are stored on a stack. The longest word ends up on the top of the stack.

include lib/stmstack.4th               \ include string stack library

: check-word                           ( a n -- a n f)
  2dup bl >r                           \ start off with a space
  begin
    dup                                \ when not end of word
  while
    over c@ r@ >=                      \ check character
  while
    r> drop over c@ >r chop            \ chop character off
  repeat r> drop nip 0=                \ cleanup and set flag
;

: open-file                            ( -- h)
  1 dup argn = abort" Usage: ordered infile"
  args input open error? abort" Cannot open file"
  dup use                              \ return and use the handle
;

: read-file                            ( --)
  0 >r                                 \ begin with zero length
  begin
    refill                             \ EOF detected?
  while
    0 parse dup r@ >=                  \ equal or longer string length?
    if                                 \ check the word and adjust length
      check-word if r> drop dup >r >s else 2drop then
    else                               \ if it checks out, put on the stack
      2drop                            \ otherwise drop the word
    then
  repeat r> drop                       \ clean it up
;

: read-back                            ( --)
  s> dup >r type cr                    \ longest string is on top of stack
  begin s> dup r@ >= while type cr repeat
  2drop r> drop                        \ keep printing until shorter word 
;                                      \ has been found

: ordered                              ( --)
  open-file s.clear read-file read-back close
;                                      \ open file, clear the stack, read file
                                       \ read it back and close the file
ordered

Since the longest word is on top of the stack, the only thing to be done is to pop all words from the stack until a shorter word is encountered. Consequently, all words are listed in reverse order:

knotty
glossy
floppy
effort
choppy
choosy
chilly
biopsy
billow
bellow
almost
accost
access
accept
accent
abbott

Fortran

!***************************************************************************************
 module ordered_module
!***************************************************************************************
 implicit none 

	!the dictionary file:
	integer,parameter :: file_unit = 1000
	character(len=*),parameter :: filename = 'unixdict.txt'

	!maximum number of characters in a word:
	integer,parameter :: max_chars = 50

	type word 
	  character(len=max_chars) :: str    !the word from the dictionary
	  integer	:: n = 0    !length of this word
	  logical	:: ordered = .false.    !if it is an ordered word
	end type word
 
	!the dictionary structure:
	type(word),dimension(:),allocatable :: dict
 
	contains
!***************************************************************************************
 
	!******************************************************************************
		function count_lines_in_file(fid) result(n_lines)
	!******************************************************************************
		implicit none
 
		integer             :: n_lines
		integer,intent(in)  :: fid		
		character(len=1)    :: tmp
		integer             :: i
		integer             :: ios
 
		!the file is assumed to be open already.
 
		rewind(fid)	  !rewind to beginning of the file
 
		n_lines = 0
		do !read each line until the end of the file.
			read(fid,'(A1)',iostat=ios) tmp
			if (ios < 0) exit      !End of file
			n_lines = n_lines + 1  !row counter
		end do
 
		rewind(fid)   !rewind to beginning of the file	
 
	!******************************************************************************
		end function count_lines_in_file
	!******************************************************************************

	!******************************************************************************
	 pure elemental function ordered_word(word) result(yn)
	!******************************************************************************
	! turns true if word is an ordered word, false if it is not.
	!******************************************************************************
	 
	 implicit none
	 character(len=*),intent(in) :: word
	 logical :: yn
	 
	 integer :: i
	 
	 yn = .true.
	 do i=1,len_trim(word)-1
	 	if (ichar(word(i+1:i+1))<ichar(word(i:i))) then
	 		yn = .false.
	 		exit
	 	end if
	 end do
	 
	!******************************************************************************
	 end function ordered_word
	!******************************************************************************
 
!***************************************************************************************
 end module ordered_module
!***************************************************************************************

!****************************************************
 program main
!****************************************************
 use ordered_module
 implicit none

	integer :: i,n,n_max
 
	!open the dictionary and read in all the words:
	open(unit=file_unit,file=filename)     		!open the file
	n = count_lines_in_file(file_unit)      !count lines in the file
	allocate(dict(n))                       !allocate dictionary structure
	do i=1,n                                !
		read(file_unit,'(A)') dict(i)%str   !each line is a word in the dictionary
		dict(i)%n = len_trim(dict(i)%str)   !save word length
	end do		
	close(file_unit)                        !close the file

	!use elemental procedure to get ordered words:
	dict%ordered = ordered_word(dict%str)	

	!max length of an ordered word:
	n_max = maxval(dict%n, mask=dict%ordered)
		
	!write the output:
	do i=1,n
		if (dict(i)%ordered .and. dict(i)%n==n_max) write(*,'(A,A)',advance='NO') trim(dict(i)%str),' '
	end do
	write(*,*) ''

!****************************************************
 end program main
!****************************************************

Output

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

FreeBASIC

' FB 1.05.0 Win64

Function isOrdered(s As Const String) As Boolean
  If Len(s) <= 1 Then Return True
  For i As Integer = 1 To Len(s) - 1
    If s[i] < s[i - 1] Then Return False
  Next 
  Return True
End Function

Dim words() As String
Dim word As String
Dim maxLength As Integer = 0
Dim count As Integer = 0 
Open "undict.txt" For Input As #1
While Not Eof(1)
  Line Input #1, word
  If isOrdered(word) Then
    If Len(word) = maxLength Then
      Redim Preserve words(0 To count)
      words(count) = word
      count += 1
    ElseIf Len(word) > maxLength Then
      Erase words
      maxLength = Len(word)
      Redim words(0 To 0)
      words(0) = word
      count = 1
    End If
  End If
Wend

Close #1

Print "The ordered words with the longest length ("; Str(maxLength); ") in undict.txt are :"
Print
For i As Integer = 0 To UBound(words)
  Print words(i)
Next
Print
Print "Press any key to quit"
Sleep

Output:

The ordered words with the longest length (6) in undict.txt are :

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Frink

url="https://web.archive.org/web/20180611003215if_/http://www.puzzlers.org:80/pub/wordlists/unixdict.txt"
a = sort[select[lines[url], {|w| charList[w] == sort[charList[w]] } ], {|a,b| length[a] <=> length[b]}]
println[sort[select[a, {|w, longest| length[w] == longest}, length[last[a]]]]]

Output:

[abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty]

FutureBasic

#plist NSAppTransportSecurity @{NSAllowsArbitraryLoads:YES}

local fn Words as CFArrayRef
  CFURLRef    url = fn URLWithString( @"https://web.archive.org/web/20180611003215/http://www.puzzlers.org/pub/wordlists/unixdict.txt" )
  CFStringRef string = fn StringWithContentsOfURL( url, NSUTF8StringEncoding, NULL )
end fn = fn StringComponentsSeparatedByCharactersInSet( string, fn CharacterSetNewlineSet )


local fn IsOrderedWord( string as CFStringRef ) as BOOL
  BOOL    flag = YES
  long    i
  unichar chr, prevChr = 0
  
  for i = 0 to len(string) - 1
    chr = fn StringCharacterAtIndex( string, i )
    if ( chr < prevChr )
      flag = NO : break
    end if
    prevChr = chr
  next
end fn = flag


void local fn DoIt
  CFStringRef        string
  CFArrayRef         words = fn Words
  long               length, maxLen = 0
  CFMutableStringRef orderedWords = fn MutableStringWithCapacity(0)
  
  for string in words
    length = len(string)
    if ( length < maxLen ) then continue
    if ( fn IsOrderedWord( string ) )
      if ( length > maxLen )
        MutableStringSetString( orderedWords, @"" )
        maxLen = length
      end if
      MutableStringAppendFormat( orderedWords, @"%@\n", string )
    end if
  next
  
  print orderedWords
end fn

fn DoIt

HandleEvents

Gambas

Public Sub Main()
Dim sDict As String = File.Load(User.Home &/ "unixdict.txt")  'Store the 'Dictionary'
Dim sOrdered As New String[]                                  'To store ordered words
Dim sHold As New String[]                                     'General store
Dim sTemp As String                                           'Temp variable
Dim siCount As Short                                          'Counter

For Each sTemp In Split(sDict, gb.NewLine)                    'For each word in the Dictionary
  For siCount = 1 To Len(sTemp)                               'Loop for each letter in the word
    sHold.Add(Mid(sTemp, siCount, 1))                         'Put each letter in sHold array
  Next
  sHold.Sort()                                                'Sort sHold (abbott = abboot, zoom = mooz)
  If sTemp = sHold.Join("") Then sOrdered.Add(sTemp)          'If they are the same (abbott(OK) mooz(not OK)) then add to sOrdered
  sHold.Clear                                                 'Empty sHold
Next

siCount = 0                                                   'Reset siCount

For Each sTemp In sOrdered                                    'For each of the Ordered words
  If Len(sTemp) > siCount Then siCount = Len(sTemp)           'Count the length of the word and keep a record of the longest length
Next

For Each sTemp In sOrdered                                    'For each of the Ordered words
  If Len(sTemp) = siCount Then sHold.Add(sTemp)               'If it is one of the longest add it to sHold
Next

sHold.Sort()                                                  'Sort sHold
Print sHold.Join(gb.NewLine)                                  'Display the result

End

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Go

Go has strings and Unicode and stuff, but with the dictionary all ASCII and lower case, strings and Unicode seem overkill. I just worked with byte slices here, only converting the final result to strings for easy output.

package main

import (
    "bytes"
    "fmt"
    "io/ioutil"
)

func main() {
    // read into memory in one chunk
    b, err := ioutil.ReadFile("unixdict.txt")
    if err != nil {
        fmt.Println(err)
        return
    }
    // split at line ends
    bss := bytes.Split(b, []byte{'\n'})

    // accumulate result
    var longest int
    var list [][]byte
    for _, bs := range bss {
        // don't bother with words shorter than
        // our current longest ordered word
        if len(bs) < longest {
            continue
        }
        // check for ordered property
        var lastLetter byte
        for i := 0; ; i++ {
            if i == len(bs) {
                // end of word.  it's an ordered word.
                // save it and break from loop
                if len(bs) > longest {
                    longest = len(bs)
                    list = list[:0]
                }
                list = append(list, bs)
                break
            }
            // check next letter
            b := bs[i]
            if b < 'a' || b > 'z' {
                continue // not a letter.  ignore.
            }
            if b < lastLetter {
                break // word not ordered.
            }
            // letter passes test
            lastLetter = b
        }
    }
    // print result
    for _, bs := range list {
        fmt.Println(string(bs))
    }
}

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Groovy

Solution:

def isOrdered = { word -> def letters = word as List; letters == ([] + letters).sort() }
assert isOrdered('abbey')
assert !isOrdered('cat')

def dictUrl = new URL('http://www.puzzlers.org/pub/wordlists/unixdict.txt')
def orderedWords = dictUrl.readLines().findAll { isOrdered(it) }
def owMax = orderedWords*.size().max()

orderedWords.findAll { it.size() == owMax }.each { println it }

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Haskell

-- Words are read from the standard input.  We keep in memory only the current
-- set of longest, ordered words.
-- 
-- Limitation: the locale's collation order is not take into consideration.

isOrdered wws@(_:ws) = and $ zipWith (<=) wws ws

longestOrderedWords = reverse . snd . foldl f (0,[]) . filter isOrdered
  where f (max, acc) w =
          let len = length w in 
          case compare len max of
            LT -> (max, acc)
            EQ -> (max, w:acc)
            GT -> (len, [w])

main = do
  str <- getContents
  let ws = longestOrderedWords $ words str
  mapM_ putStrLn ws

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Alternative version:

import Control.Monad (liftM)

isSorted wws@(_ : ws) = and $ zipWith (<=) wws ws

getLines = liftM lines . readFile

main = do
    ls <- getLines "unixdict.txt"
    let ow = filter isSorted ls
    let maxl = foldr max 0 (map length ow)
    print $ filter (\w -> (length w) == maxl) ow

Huginn

import Algorithms as algo;
import Mathematics as math;
import Network as net;
import Text as text;

main( argv_ ) {
  url = size( argv_ ) > 1
    ? argv_[1]
    : "http://wiki.puzzlers.org/pub/wordlists/unixdict.txt";
  words = algo.materialize( algo.map( net.get( url ).stream, string.strip ), list );
  ordered = algo.materialize(
    algo.filter(
      words,
      @( word ){ word == ∑( algo.map( algo.sorted( word ), string ) ); }
    ),
    list
  );
  maxLen = algo.reduce( ordered, @( x, y ){ math.max( x, size( y ) ); }, 0 );
  maxOrderedWords = algo.materialize(
    algo.filter( ordered, @[maxLen]( word ){ size( word ) == maxLen; } ),
    list
  );
  print( "{}\n".format( text.join( algo.sorted( maxOrderedWords ), " " ) ) );
  return ( 0 );
}

Icon and Unicon

link strings

procedure main(A)
   f := open(\A[1]) | stop("Give dictionary file name on command line")
   every (maxLen := 0, maxLen <= *(w := !f), w == csort(w)) do {
      if maxLen <:= *w then maxList := []  #discard any shorter sorted words 
      put(maxList, w)
      }
   every write(!\maxList)
end

Library: Icon Programming Library

strings provides csort which sorts the letters within a string

Output:

->ordered_words unixdict.txt
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty
->

Io

file := File clone openForReading("./unixdict.txt")
words := file readLines
file close

maxLen := 0
orderedWords := list()
words foreach(word,
    if( (word size >= maxLen) and (word == (word asMutable sort)),
        if( word size > maxLen,
            maxLen = word size
            orderedWords empty
        )
        orderedWords append(word)
    )
)

orderedWords join(" ") println

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

J

NB. from http://wiki.puzzlers.org/pub/wordlists/unixdict.txt
   oWords=: (#~ ] = /:~L:0) cutLF fread 'unixdict.txt'
   ;:inv (#~ (= >./)@:(#@>)) oWords
abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Recap:

read dictionary (fread 'unixdict.txt')
break into words, one per line (cutLF)
find ordered words ((#~ ] = /:~L:0))
select the longest ordered words ((#~ (= >./)@:(#@>))oWords)
format for display (using ;:inv)

Java

Works with: Java version 1.5+

This example assumes there is a local copy of the dictionary whose path is given as the first argument to the program.

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;

public class Ordered {

	private static boolean isOrderedWord(String word){
		char[] sortedWord = word.toCharArray();
		Arrays.sort(sortedWord);
		return word.equals(new String(sortedWord));
	}
	
	public static void main(String[] args) throws IOException{
		List<String> orderedWords = new LinkedList<String>();
		BufferedReader in = new BufferedReader(new FileReader(args[0]));
		while(in.ready()){
			String word = in.readLine();
			if(isOrderedWord(word)) orderedWords.add(word);
		}
		in.close();
		
		Collections.<String>sort(orderedWords, new Comparator<String>() {
			@Override
			public int compare(String o1, String o2) {
				return new Integer(o2.length()).compareTo(o1.length());
			}
		});
		
		int maxLen = orderedWords.get(0).length();
		for(String word: orderedWords){
			if(word.length() == maxLen){
				System.out.println(word);
			}else{
				break;
			}
		}
	}
}

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Using Java 16

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;

public final class OrderedWords {

	public static void main(String[] aArgs) throws IOException {
		List<String> ordered = Files.lines(Path.of("unixdict.txt"))
				                    .filter( word -> isOrdered(word) ).toList();
	    	    
	    final int maxLength = ordered.stream().map( word -> word.length() ).max(Integer::compare).get();
	    ordered.stream().filter( word -> word.length() == maxLength ).forEach(System.out::println);	   
	}
	
	private static boolean isOrdered(String aWord) {
		return aWord.chars()
				    .mapToObj( i -> (char) i )
				    .sorted()
				    .map(String::valueOf)
				    .reduce("", String::concat)
				    .equals(aWord);
	}

}

The same as the Java example above.

JavaScript

Using node.js:

var fs = require('fs'), print = require('sys').print;
fs.readFile('./unixdict.txt', 'ascii', function (err, data) {
    var is_ordered = function(word){return word.split('').sort().join('') === word;},
        ordered_words = data.split('\n').filter(is_ordered).sort(function(a, b){return a.length - b.length}).reverse(),
        longest = [], curr = len = ordered_words[0].length, lcv = 0;
    while (curr === len){
        longest.push(ordered_words[lcv]);
        curr = ordered_words[++lcv].length;
    };
    print(longest.sort().join(', ') + '\n');
});

Output:

abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty

Alternative version (also using Node.js):

var http = require('http');

http.get({
  host: 'www.puzzlers.org',
  path: '/pub/wordlists/unixdict.txt'
}, function(res) {
  var data = '';
  res.on('data', function(chunk) {
    data += chunk;
  });
  res.on('end', function() {
    var words = data.split('\n');
    var max = 0;
    var ordered = [];
    words.forEach(function(word) {
      if (word.split('').sort().join('') != word) return;
      if (word.length == max) {
        ordered.push(word);
      } else if (word.length > max) {
        ordered = [word];
        max = word.length;
      }
    });
    console.log(ordered.join(', '));
  });
});

jq

Works with: jq version 1.4

def is_sorted:
  if length <= 1 then true
  else .[0] <= .[1] and (.[1:] | is_sorted)
  end;

def longest_ordered_words:
  # avoid string manipulation:
  def is_ordered: explode | is_sorted;
  map(select(is_ordered))
  | (map(length)|max) as $max
  | map( select(length == $max) );


split("\n")  | longest_ordered_words

Output:

["abbott","accent","accept","access","accost","almost","bellow","billow","biopsy","chilly","choosy","choppy","effort","floppy","glossy","knotty"]

Julia

Works with: Julia version 0.6

Built-in function:

issorted("abc") # true

Main:

lst = readlines("data/unixdict.txt")
filter!(issorted, lst)
filter!(x -> length(x) == maximum(length, lst), lst)
println.(lst)

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

K

    w@&d=|/d:#:'w:d@&&/'{~x<y}':'d:0:"unixdict.txt"
("abbott"
 "accent"
 "accept"
 "access"
 "accost"
 "almost"
 "bellow"
 "billow"
 "biopsy"
 "chilly"
 "choosy"
 "choppy"
 "effort"
 "floppy"
 "glossy"
 "knotty")

Kotlin

import java.net.URI

fun main() {
    val url = URI(
        "https://web.archive.org/web/20180611003215/http://www.puzzlers.org/pub/wordlists/unixdict.txt"
    ).toURL()
    val words = url.openStream().bufferedReader().use {
        var max = 0
        it.lineSequence()
            .filter { it.asSequence().windowed(2).all { it[0] <= it[1] } }
            .sortedByDescending(String::length)
            .takeWhile { word -> word.length >= max.also { max = word.length } }
            .toList()
    }
    words.forEach(::println)
}

Lambdatalk

{def maxOrderedWords 

 {def isOrdered
  {lambda {:w}
   {W.equal? :w {W.sort before :w}}}}

 {def getOrdered
  {lambda {:w}
   {if {isOrdered :w} then :w else}}}

 {def pushOrdered 
  {lambda {:m :w}
   {if {= {W.length :w} :m} then {br}:w else}}}

 {def maxOrderedWords.i
  {lambda {:sortedWords}
   {let { {:orderedWords {S.map getOrdered :sortedWords}} }
        {S.map {{lambda {:m :w} {pushOrdered :m :w}} 
                        {max {S.map {lambda {:w} {W.length :w}}
                                    :orderedWords}}}
                :orderedWords}}}} 

 {lambda {:s}
  {maxOrderedWords.i {S.replace else by el_se in :s}}}}  
-> maxOrderedWords 

{maxOrderedWords UNIX.DICT}
->         
abbott        
accent 
accept 
access 
accost                               
almost                                       
bellow                  
billow   
biopsy                                 
chilly    
choosy  
choppy                                                                   
effort                                    
floppy                             
glossy                                                            
knotty

Lang5

: >string-index
    "" split
    "&'0123456789abcdefghijklmnopqrstuvwxyz" "" split
    swap index collapse ;
: chars  "" split length swap drop ;
: cr  "\n" . ;
: nip  swap drop ;
: ordered?
    dup grade subscript != '+ reduce if 0 else -1 then ;

: filtering
    [] '_ set
    0 do read 
        2dup chars
        <=
        if  dup >string-index ordered?
            if   2dup chars
                 <
                 if   nip dup chars swap
                      [] '_ set
                 then
                 _ swap append '_ set
                 '. .                       # progress dot
            else drop
            then
        else drop
        then
    eof if break then loop

    cr _ . cr
    ;

: ordered-words
    '< 'unixdict.txt open 'fh set
    fh fin filtering fh close ;

ordered-words

Output:

[ abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty ]

Lasso

local(f = file('unixdict.txt'), words = array, ordered = array, maxleng = 0)
#f->dowithclose => {
	#f->foreachLine => {
		#words->insert(#1)
	}
}
with w in #words
do => {
	local(tosort = #w->asString->values)
	#tosort->sort
	if(#w->asString == #tosort->join('')) => {
		#ordered->insert(#w->asString)
		#w->asString->size > #maxleng ? #maxleng = #w->asString->size
	}
}
with w in #ordered
where #w->size == #maxleng
do => {^ #w + '\r' ^}

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Liberty BASIC

'Ordered wordsFrom Rosetta Code
open "unixdict.txt" for input as #1
'this is not normal DOS/Windows file.
'It LF delimited, not CR LF
'So Line input would not work.

lf$=chr$(10)
curLen=0
wordList$=""
while not(eof(#1))
    a$=inputto$(#1, lf$)
    'now, check word
    flag = 1
    c$ = left$(a$,1)
    for i = 2 to len(a$)
        d$ = mid$(a$,i,1)
        if c$>d$ then flag=0: exit for
        c$=d$
    next
    'ckecked, proceed if ordered word
    if flag then
        if curLen=len(a$) then
            wordList$=wordList$+" "+a$
        else
            if curLen<len(a$) then
                curLen=len(a$)
                wordList$=a$
            end if
        end if
    end if
wend
close #1
print wordList$

Output:

abbott 
accent 
accept 
access 
accost 
almost 
bellow 
billow 
biopsy 
chilly 
choosy 
choppy 
effort 
floppy 
glossy 
knotty

Lingo

Code ported from Lua solution.

-- Contents of unixdict.txt passed as string
on printLongestOrderedWords (words)
  res = []
  maxlen = 0
  _player.itemDelimiter = numtochar(10)
  cnt = words.item.count
  repeat with i = 1 to cnt
    w = words.item[i]
    len = w.length
    ordered = TRUE
    repeat with j = 2 to len
      if chartonum(w.char[j-1])>chartonum(w.char[j]) then
        ordered = FALSE
        exit repeat
      end if
    end repeat
    if ordered then
      if len > maxlen then
        res = [w]
        maxlen = len
      else if len = maxlen then
        res.add(w)
      end if
    end if
  end repeat
  put res
end

Output:

-- ["abbott", "accent", "accept", "access", "accost", "almost", "bellow", "billow", "biopsy", "chilly", "choosy", "choppy", "effort", "floppy", "glossy", "knotty"]

Lua

fp = io.open( "dictionary.txt" )

maxlen = 0
list = {}

for w in fp:lines() do
    ordered = true
    for l = 2, string.len(w) do
	if string.byte( w, l-1 ) > string.byte( w, l ) then
	    ordered = false
  	    break
	end
    end
    if ordered then
	if string.len(w) > maxlen then
	    list = {}
	    list[1] = w
	    maxlen = string.len(w)
	elseif string.len(w) == maxlen then
	    list[#list+1] = w
	end
    end
end

for _, w in pairs(list) do
    print( w )
end

fp:close()

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Maple

lst := StringTools:-Split(Import("http://www.puzzlers.org/pub/wordlists/unixdict.txt"), "\n"):
longest := 0:
words := Array():
i := 1:
for word in lst do
	if StringTools:-IsSorted(word) then
		len := StringTools:-Length(word):
		if len > longest then
			longest := len:
			words := Array():
			words(1) := word:
			i := 2:
		elif len = longest then
			words(i) := word:
			i++:
		end if;
	end if;
end do;
for word in words do print(word); end do;

Output:

"abbott"
"accent"
"accept"
"access"
"accost"
"almost"
"bellow"
"billow"
"biopsy"
"chilly"
"choosy"
"choppy"
"effort"
"floppy"
"glossy"
"knotty"

Mathematica/Wolfram Language

Module[{max, 
   data = Select[Import["http://www.puzzlers.org/pub/wordlists/unixdict.txt", "List"], 
     OrderedQ[Characters[#]] &]},
  max = Max[StringLength /@ data];
  Select[data, StringLength[#] == max &]]

However Mathematica has built in dictionaries for many languages, so here is a more general version...

maxWords[language_String] :=  Module[{max,data = Select[DictionaryLookup[{language, "*"}],OrderedQ[Characters[#]] &]},
  max = Max[StringLength /@ data];
  Select[data, StringLength[#] == max &]]

findLargestOrderedWord["English"]
{"billowy"}

findLargestOrderedWord["French"]
{"accent", "afflux", "bijoux", "billot", "dehors", "effort"}

findLargestOrderedWord["Spanish"]
{"abenuz", "chillo"}

MATLAB / Octave

maxlen = 0; 
listlen= 0; 
fid = fopen('unixdict.txt','r');
while ~feof(fid)
    str = fgetl(fid);
    if any(diff(abs(str))<0) continue; end; 
    
    if length(str)>maxlen, 
	list = {str};
	maxlen = length(str); 
    elseif length(str)==maxlen, 
	list{end+1} = str;
    end;
end
fclose(fid);
printf('%s\n',list{:});

Returns:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Nanoquery

import Nanoquery.IO

def is_ordered(word)
    word = str(word)
    if len(word) < 2
        return true
    end

    for i in range(1, len(word) - 1)
        if str(word[i]) < str(word[i - 1])
            return false
        end
    end

    return true
end

longest = 0
words = {}
for word in new(File, "unixdict.txt").read()
    if is_ordered(word)
        if len(word) > longest
            longest = len(word)
            words.clear()
            words.append(word)
        else if len(word) = longest
            words.append(word)
        end
    end
end
println words

Output:

[abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty]

NetRexx

/* NetRexx */
options replace format comments java crossref savelog symbols binary

unixdict = 'unixdict.txt'
do
  wmax = Integer.MIN_VALUE
  dwords = ArrayList()
  inrdr = BufferedReader(FileReader(File(unixdict)))
  loop label ln while inrdr.ready
    dword = Rexx(inrdr.readLine).strip
    if isOrdered(dword) then do
      dwords.add(dword)
      if dword.length > wmax then
        wmax = dword.length
      end
    end ln
  inrdr.close

  witerator = dwords.listIterator
  loop label wd while witerator.hasNext
    dword = Rexx witerator.next
    if dword.length < wmax then do
      witerator.remove
      end
    end wd
  dwords.trimToSize

  say dwords.toString

catch ex = IOException
  ex.printStackTrace
end

return

method isOrdered(dword = String) inheritable static binary returns boolean
  wchars = dword.toCharArray
  Arrays.sort(wchars)
  return dword.equalsIgnoreCase(String(wchars))

Output

[abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty]

Nim

import strutils

const DictFile = "unixdict.txt"

func isSorted(s: string): bool =
  var last = char.low
  for c in s:
    if c < last: return false
    last = c
  result = true

var
  mx = 0
  words: seq[string]

for word in DictFile.lines:
  if word.len >= mx and word.isSorted:
    if word.len > mx:
      words.setLen(0)
      mx = word.len
    words.add word
echo words.join(" ")

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

OCaml

let input_line_opt ic =
  try Some(input_line ic)
  with End_of_file -> None

(* load each line in a list *)
let read_lines ic =
  let rec aux acc =
    match input_line_opt ic with
    | Some line -> aux (line :: acc)
    | None -> (List.rev acc)
  in
  aux []

let char_list_of_string str =
  let lst = ref [] in
  String.iter (fun c -> lst := c :: !lst) str;
  (List.rev !lst)

let is_ordered word =
  let rec aux = function
    | c1::c2::tl ->
        if c1 <= c2
        then aux (c2::tl)
        else false
    | c::[] -> true
    | [] -> true  (* should only occur with an empty string *)
  in
  aux (char_list_of_string word)

let longest_words words =
  let res, _ =
    List.fold_left
      (fun (lst, n) word ->
        let len = String.length word in
        let comp = compare len n in
        match lst, comp with
        | lst, 0  -> ((word::lst), n) (* len = n *)
        | lst, -1 -> (lst, n)         (* len < n *)
        | _, 1    -> ([word], len)    (* len > n *)
        | _ -> assert false
      )
      ([""], 0) words
  in
  (List.rev res)

let () =
  let ic = open_in "unixdict.txt" in
  let words = read_lines ic in
  let lower_words = List.map String.lowercase words in
  let ordered_words = List.filter is_ordered lower_words in
  let longest_ordered_words = longest_words ordered_words in
  List.iter print_endline longest_ordered_words

Output:

$ ocaml ordered_words.ml 
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Oforth

: longWords
| w longest l s |
   0 ->longest
   File new("unixdict.txt") forEach: w [
      w size dup ->s longest < ifTrue: [ continue ]
      w sort w == ifFalse: [ continue ]
      s longest > ifTrue: [ s ->longest ListBuffer new ->l ]
      l add(w)
      ] l ;

Output:

>longWords .
[abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty]

ooRexx

Translation of: REXX

Adapted for ooRexx

/*REXX list (the longest) ordered word(s) from a supplied dictionary. */
iFID= 'UNIXDICT.TXT'
w.=''
mL=0
Do j=1 While lines(iFID)\==0
  x=linein(iFID)
  w=length(x)
  If w>=mL Then Do
    Parse Upper Var x xU 1 z 2
    Do k=2 To w
      _=substr(xU, k, 1)
      If \datatype(_, 'U')  Then Iterate
      If _<z                Then Iterate j
      z=_
      End
    mL=w
    w.w=w.w  x
    End
  End
nn=words(w.mL)
Say nn 'word's(nn) "found (of length" mL')'
Say ''
Do n=1 To nn
  Say word(w.mL, n)
  End
Exit
s: Return left('s',arg(1)>1)

Output:

Same as REXX'

PARI/GP

ordered(s)=my(v=Vecsmall(s),t=97);for(i=1,#v,if(v[i]>64&&v[i]<91,v[i]+=32);if(v[i]<97||v[i]>122||v[i]<t,return(0),t=v[i]));1
v=select(ordered,readstr("~/unixdict.txt"));
N=vecmax(apply(length,v));
select(s->#s==N, v)

Output:

%1 = ["abbott", "accent", "accept", "access", "accost", "almost", "bellow", "billow", "biopsy", "chilly", "choosy", "choppy", "effort", "floppy", "glossy", "knotty"]

Perl

#!/usr/bin/perl
use strict;
use warnings;

open(FH, "<", "unixdict.txt") or die "Can't open file!\n";
my @words;
while (<FH>) {
   chomp;
   push @{$words[length]}, $_ if $_ eq join("", sort split(//));
}
close FH;
print "@{$words[-1]}\n";

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Phix

with javascript_semantics
sequence words = unix_dict()
integer maxlen = -1, found = 0
for i=1 to length(words) do
    string word = words[i]
    integer l = length(word)
    if l>=maxlen and word=sort(word) then
        if l>maxlen then {found,maxlen} = {0,l} end if
        found += 1
        words[found] = word
    end if
end for
printf(1,"The %d longest ordered words:\n %s\n",{found,join_by(words[1..found],1,4," ","\n ")})

Output:

The 16 longest ordered words:
 abbott accent accept access
 accost almost bellow billow
 biopsy chilly choosy choppy
 effort floppy glossy knotty

Phixmonti

include ..\Utilitys.pmt

0 var maxlen
( ) var words
0 var f

def getword f fgets dup -1 == if drop false else -1 del endif enddef
def ordered? dup dup sort == enddef
def greater? len maxlen > enddef

"unixdict.txt" "r" fopen var f
f -1 !=
while
    getword dup if
        ordered? if
            greater? if
                len var maxlen
                ( ) var words
            endif
            len maxlen == if
                words over 0 put var words
            endif
        endif
    endif
endwhile 
f fclose
words print

Another solution

include ..\Utilitys.pmt

0 var f

def getword f fgets dup -1 == if drop false else -1 del endif enddef
def ordered? dup dup sort == enddef
def greater? len rot 1 get len nip rot swap over over > enddef
def append over 0 put enddef

( " " )

"unixdict.txt" "r" fopen var f
f -1 !=
while
    getword dup if
        ordered? if
            greater? if
                drop drop flush append
            else
                == if append endif
            endif
            swap
        endif
    endif
endwhile 
f fclose
print

Output:

["abbott", "accent", "accept", "access", "accost", "almost", "bellow", "billow", "biopsy", "chilly", "choosy", "choppy", "effort", "floppy", "glossy", "knotty"]

Picat

go =>
   Dict = "unixdict.txt",
   Words = new_map([Word=Word.length : Word in read_file_lines(Dict), Word == Word.sort()]),
   MaxLen = max([Len : _Word=Len in Words]),
   println([Word : Word=Len in Words, Len=MaxLen].sort).

Output:

[abbott,accent,accept,access,accost,almost,bellow,billow,biopsy,chilly,choosy,choppy,effort,floppy,glossy,knotty]

PicoLisp

(in "unixdict.txt"
   (mapc prinl
      (maxi '((L) (length (car L)))
         (by length group
            (filter '((S) (apply <= S))
               (make (while (line) (link @))) ) ) ) ) )

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

PL/I

order: procedure options (main);               /* 24/11/2011 */
   declare word      character (20) varying;
   declare word_list character (20) varying controlled;
   declare max_length fixed binary;
   declare input file;

   open file (input) title ('/ORDER.DAT,TYPE(TEXT),RECSIZE(100)');

   on endfile (input) go to completed_search;

   max_length = 0;
   do forever;
      get file (input) edit (word) (L);
      if length(word) > max_length then
         do;
            if in_order(word) then
               do;
                  /* Get rid of any stockpiled shorter words. */
                  do while (allocation(word_list) > 0);
                     free word_list;
                  end;
                  /* Add the eligible word to the stockpile. */
                  allocate word_list;
                  word_list = word;
                  max_length = length(word);
               end;
         end;
      else if max_length = length(word) then
         do; /* we have an eligle word of the same (i.e., maximum) length. */
            if in_order(word) then
               do; /* Add it to the stockpile. */
                  allocate word_list;
                  word_list = word;
               end;
         end;
   end;
completed_search:
   put skip list ('There are ' || trim(allocation(word_list)) ||
      ' eligible words of length ' || trim(length(word)) || ':');
   do while (allocation(word_list) > 0);
      put skip list (word_list);
      free word_list;
   end;

/* Check that the letters of the word are in non-decreasing order of rank. */
in_order: procedure (word) returns (bit(1));
   declare word character (*) varying;
   declare i fixed binary;

   do i = 1 to length(word)-1;
      if substr(word, i, 1) > substr(word, i+1, 1) then return ('0'b);
   end;
   return ('1'b);
end in_order;
end order;

OUTPUT:

There are 16 eligible words of length 6: 
knotty 
glossy 
floppy 
effort 
choppy 
choosy 
chilly 
biopsy 
billow 
bellow 
almost 
accost 
access 
accept 
accent 
abbott

PowerShell

$url = 'http://www.puzzlers.org/pub/wordlists/unixdict.txt'

(New-Object System.Net.WebClient).DownloadFile($url, "$env:TEMP\unixdict.txt")

$ordered = Get-Content -Path "$env:TEMP\unixdict.txt" |
    ForEach-Object {if (($_.ToCharArray() | Sort-Object) -join '' -eq $_) {$_}} |
    Group-Object  -Property Length |
    Sort-Object   -Property Name |
    Select-Object -Property @{Name="WordCount" ; Expression={$_.Count}},
                            @{Name="WordLength"; Expression={[int]$_.Name}},
                            @{Name="Words"     ; Expression={$_.Group}} -Last 1

"There are {0} ordered words of the longest word length ({1} characters):`n`n{2}" -f $ordered.WordCount,
                                                                                     $ordered.WordLength,
                                                                                    ($ordered.Words -join ", ")
Remove-Item -Path "$env:TEMP\unixdict.txt" -Force -ErrorAction SilentlyContinue

Output:

There are 16 ordered words of the longest word length (6 characters):

abbott, accent, accept, access, accost, almost, bellow, billow, biopsy, chilly, choosy, choppy, effort, floppy, glossy, knotty

Prolog

Works with SWI-Prolog

:- use_module(library( http/http_open )).

ordered_words :-
        % we read the URL of the words
	http_open('http://www.puzzlers.org/pub/wordlists/unixdict.txt',	In, []),
	read_file(In, [], Out),
	close(In),

        % we get a list of pairs key-value where key = Length and value = <list-of-its-codes>
        % this list must be sorted
	msort(Out, MOut),

	group_pairs_by_key(MOut, POut),

       % we sorted this list in decreasing order of the length of values
	predsort(my_compare, POut, [_N-V | _OutSort]),
	maplist(mwritef, V).


mwritef(V) :-
	writef('%s\n', [V]).

read_file(In, L, L1) :-
	read_line_to_codes(In, W),
	(   W == end_of_file ->
               % the file is read
	       L1 = L
	       ;
               % we sort the list of codes of the line
	       % and keep only the "goods word"
	       (   msort(W, W) ->
	           length(W, N), L2 = [N-W | L], (len = 6 -> writef('%s\n', [W]); true)
	       ;
	           L2 = L
	       ),

               % and we have the pair Key-Value in the result list
	       read_file(In, L2, L1)).

% predicate for sorting list of pairs Key-Values
% if the lentgh of values is the same
% we sort the keys in alhabetic order
my_compare(R, K1-_V1, K2-_V2) :-
	(   K1 < K2 -> R = >; K1 > K2 -> R = <; =).

Output :

 ?- ordered_words.
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty
true.

PureBasic

Procedure.s sortLetters(*word.Character, wordLength) ;returns a string with the letters of a word sorted
  Protected Dim letters.c(wordLength)
  Protected *letAdr = @letters()
 
  CopyMemoryString(*word, @*letAdr)
  SortArray(letters(), #PB_Sort_Ascending, 0, wordLength - 1)
  ProcedureReturn PeekS(@letters(), wordLength)
EndProcedure
 
Structure orderedWord
  word.s
  length.i
EndStructure
 
Define filename.s = "unixdict.txt", fileNum = 0,  word.s
 
If OpenConsole()
  NewList orderedWords.orderedWord()
  If ReadFile(fileNum, filename)
    While Not Eof(fileNum)
      word = ReadString(fileNum)
      If word = sortLetters(@word, Len(word))
        AddElement(orderedWords())
        orderedWords()\word = word
        orderedWords()\length = Len(word)
      EndIf
    Wend
  Else
    MessageRequester("Error", "Unable to find dictionary '" + filename + "'")
    End
  EndIf
 
  SortStructuredList(orderedWords(), #PB_Sort_Ascending, OffsetOf(orderedWord\word), #PB_String)
  SortStructuredList(orderedWords(), #PB_Sort_Descending, OffsetOf(orderedWord\length), #PB_Integer)
  Define maxLength
  FirstElement(orderedWords())
  maxLength = orderedWords()\length
  ForEach orderedWords()
    If orderedWords()\length = maxLength
      Print(orderedWords()\word + "  ")
    EndIf
  Next 
 
  Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
  CloseConsole()
EndIf

Sample output:

abbott  accent  accept  access  accost  almost  bellow  billow  biopsy  chilly
choosy  choppy  effort  floppy  glossy  knotty

Python

Python: First Solution

import urllib.request

url = 'http://www.puzzlers.org/pub/wordlists/unixdict.txt'
words = urllib.request.urlopen(url).read().decode("utf-8").split()
ordered = [word for word in words if word==''.join(sorted(word))]
maxlen = len(max(ordered, key=len))
maxorderedwords = [word for word in ordered if len(word) == maxlen]
print(' '.join(maxorderedwords))

Python: Alternate Solution using one explicit loop

import urllib.request

mx, url = 0, 'http://www.puzzlers.org/pub/wordlists/unixdict.txt'

for word in urllib.request.urlopen(url).read().decode("utf-8").split():
    lenword = len(word)
    if lenword >= mx and word==''.join(sorted(word)):
        if lenword > mx:
            words, mx = [], lenword
        words.append(word)
print(' '.join(words))

Sample Output

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Python: As a fold

Works with: Python version 3.7

'''The longest ordered words in a list'''

from functools import reduce
from operator import le
import urllib.request


# longestOrds :: [String] -> [String]
def longestOrds(ws):
    '''The longest ordered words in a given list.
    '''
    return reduce(triage, ws, (0, []))[1]


# triage :: (Int, [String]) -> String -> (Int, [String])
def triage(nxs, w):
    '''The maximum length seen for an ordered word,
       and the ordered words of this length seen so far.
    '''
    n, xs = nxs
    lng = len(w)
    return (
        (lng, ([w] if n != lng else xs + [w])) if (
            ordered(w)
        ) else nxs
    ) if lng >= n else nxs


# ordered :: String -> Bool
def ordered(w):
    '''True if the word w is ordered.'''
    return all(map(le, w, w[1:]))


# ------------------------- TEST -------------------------
if __name__ == '__main__':
    print(
        '\n'.join(longestOrds(
            urllib.request.urlopen(
                'http://wiki.puzzlers.org/pub/wordlists/unixdict.txt'
            ).read().decode("utf-8").split()
        ))
    )

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Quackery

  [ - -1 1 clamp 1+ ]'[ swap peek do ]     is <=>      ( n n -->  )

  [ true swap
    behead swap witheach
      [ tuck > if
          [ dip not conclude ] ]
      drop ]                               is ordered (   [ --> b )

  [ stack ]                                is largest (   [ --> s )

  [ 1 largest put
    [] swap witheach
      [ dup size
        largest share <=>
          [ drop
            [ dup ordered iff
                [ nested join ]
              else drop ]
            [ dup ordered iff
                [ dup size largest replace
                  nip nested ]
              else drop ] ] ]
     largest release ]                     is task    (   [ --> [ )

  $ 'unixdict.txt' sharefile drop nest$
  task
  witheach [ echo$ sp ]

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

R

words = scan("https://web.archive.org/web/20180611003215/http://www.puzzlers.org/pub/wordlists/unixdict.txt",what = "character")

ordered = logical()
for(i in 1:length(words)){
  first = strsplit(words[i],"")[[1]][1:nchar(words[i])-1]
  second = strsplit(words[i],"")[[1]][2:nchar(words[i])]
  ordered[i] = all(first<=second)
}

cat(words[ordered][which(nchar(words[ordered])==max(nchar(words[ordered])))],sep="\n")

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Racket

#lang racket
(require net/url)

(define dict "http://www.puzzlers.org/pub/wordlists/unixdict.txt")

(define (ordered? str)
  (define lower (string-downcase str))
  (for/and ([i (in-range 1 (string-length str))])
    (char<=? (string-ref lower (sub1 i)) (string-ref lower i))))

(define words (port->lines (get-pure-port (string->url dict))))

(let loop ([len 0] [longs '()] [words words])
  (if (null? words)
    (for-each displayln (reverse longs))
    (let* ([word (car words)] [words (cdr words)]
           [wlen (string-length word)])
      (if (or (< wlen len) (not (ordered? word)))
        (loop len longs words)
        (loop wlen (cons word (if (> wlen len) '() longs)) words)))))

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Raku

(formerly Perl 6)

Here we assume the dictionary is provided on standard input.

Works with: Rakudo version 2016.07

say lines.grep({ [le] .comb }).classify(*.chars).max(*.key).value

Output:

[abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty]

Red

Red []
;; code to read url and save to local file:
;;data: read/binary http://www.puzzlers.org/pub/wordlists/unixdict.txt 
;;write %unixdict.txt data

max: [ "" ] ;; init array with one empty string (length 0 ) 

foreach word read/lines %unixdict.txt [   ;; read local file
  len: either  word = sort copy word [ length? word ] [  -1 ]   ;; check if ordered and get length
  case [
    len  > length?  first max [    max:  reduce [ word ]]       ;; init new block
    len = length? first max   [ append max word   ]     
  ]
]
probe max

Sample Output

["abbott" "accent" "accept" "access" "accost" "almost" "bellow" "billow" "biopsy" "chilly" "choosy" "choppy" "effort" "floppy" "glossy" "knotty"]

REXX

This problem assumes (or implies) an order of letter case, but fortunately, there're no uppercase letters
in the (default) dictionary to see which programs would fail when not recognizing this distinction.

In ASCII, A is less than a, while in EBCDIC, it's the other way around.

The problem can be avoided by first converting the word to a specific case, and then test for ordered
letters in that word (as indeed, this REXX entry does).

Output could be improved by sorting the words in the dictionary, but adding a sort would bulk up the program;
but since the word list (in this case) is already in alphabetical order, this would-be improvement is
mostly moot.

/*REXX program  lists  (the longest)  ordered word(s)  from a  supplied  dictionary.    */
iFID= 'UNIXDICT.TXT'                             /*the filename of the word dictionary. */
m= 1                                             /*maximum length of an ordered word(s).*/
call linein iFID, 1, 0                           /*point to the first word in dictionary*/
@.=                                              /*placeholder array for list of words. */
   do j=1  while lines(iFID)\==0; x=linein(iFID) /*keep reading until file is exhausted.*/
   w= length(x);       if w<m  then iterate      /*Word not long enough? Then ignore it.*/
   if \datatype(x, 'M')        then iterate      /*Is it not a letter?  Then ignore it. */
   parse upper var  x      xU  1  z  2           /*get uppercase version of X & 1st char*/
        do k=2  for w-1;    _= substr(xU, k, 1)  /*process each letter in uppercase word*/
        if _<z  then iterate j                   /*is letter < than the previous letter?*/
        z= _                                     /*we have a newer current letter.      */
        end   /*k*/                              /* [↑]  logic includes  ≥  order.      */
   m= w                                          /*maybe define a new maximum length.   */
   @.w= @.w  x                                   /*add the original word to a word list.*/
   end   /*j*/                                   /*the 1st DO needs an index for ITERATE*/
              #= words(@.m)                      /*just a handy─dandy variable to have. */
say #  'word's(#)  "found (of length" m')';  say /*show the number of words and length. */
        do n=1  for #;   say word(@.m, n);   end /*display all the words, one to a line.*/
exit                                             /*stick a fork in it,  we're all done. */
ghijk
/*──────────────────────────────────────────────────────────────────────────────────────*/
s:  if arg(1)==1  then return '';   return "s"   /*a simple pluralizer (merely adds "S")*/

output when using the default supplied word dictionary:

16 words found (of length 6)

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Ring

load "stdlib.ring"


cStr = read("unixdict.txt")
wordList = str2list(cStr)
sum = 0
sortList = []

see "working..." + nl + nl

for n = 1 to len(wordList) 
    num = 0
    len = len(wordList[n])-1
    for m = 1 to len
        asc1 = ascii(wordList[n][m])
        asc2 = ascii(wordList[n][m+1]) 
        if asc1 <= asc2
           num = num + 1
        ok 
    next
    if num = len 
       sum = sum + 1
       add(sortList,[wordList[n],len])
    ok
next

sortList = sort(sortList,2)
sortList = reverse(sortList)
endList = []

len = sortList[1][2]

for n = 1 to len(sortList)
    if sortList[n][2] = len
       add(endList,sortList[n][1])
    else
       exit
    ok
next

endList = sort(endList)
see endList

see nl + "done..." + nl

Output:

working...

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

done...

RPL

The only way to use unixdict.txt as input is to download it locally and to convert it into a list of 25104 strings. Fortunately, emulators can handle such a big data structure in RAM.

Works with: Halcyon Calc version 4.2.7

≪ "a" DUP 
   1 4 PICK SIZE FOR j 
      SWAP DROP 
      OVER j DUP SUB 
      IF DUP2 > THEN 99 'j' STO END
   NEXT
   ≤ SWAP DROP
≫ 'ORDWORD?' STO

≪ 0 → words sizemax
  ≪ { } 
     1 words EVAL SIZE FOR j
        words j GET DUP SIZE
        IF DUP sizemax ≥ THEN        
           IF OVER ORDWORD? THEN      @ 2-step test, rather than one with an AND, to save execution time 
              IF DUP sizemax > THEN 
                 'sizemax' STO
                 SWAP DROP { } SWAP
              ELSE DROP END
              +
           ELSE DROP2 END
        ELSE DROP2 END
     NEXT
≫ ≫ 'ORDWORDS' STO

'Unixdict' ORDWORDS

Output:

1: { abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty }

Ruby

require 'open-uri'
ordered_words = open('http://www.puzzlers.org/pub/wordlists/unixdict.txt', 'r').select do |word| 
  word.strip!
  word.chars.sort.join == word
end

grouped = ordered_words.group_by &:size
puts grouped[grouped.keys.max]

Sample Output

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Local version:

words = IO.foreach('unixdict.txt').map(&:chomp).select {|word| word.chars.sort.join == word}
puts words.group_by(&:size).sort_by(&:first).last.last

Run BASIC

a$	= httpget$("http://www.puzzlers.org/pub/wordlists/unixdict.txt")
j	= 1
i   	= instr(a$,chr$(10),j)
while i <> 0
 a1$ 	= mid$(a$,j,i-j)
 for k	= 1 to len(a1$) - 1
  if mid$(a1$,k,1) > mid$(a1$,k+1,1) then goto [noWay]
 next k
 maxL	= max(maxL,len(a1$))
if len(a1$) >= maxL then a2$ = a2$ + a1$ + "||"
[noWay]
j	= i + 1
i   	= instr(a$,chr$(10),j)
wend
n	= 1
while  word$(a2$,n,"||") <> ""
 a3$ = word$(a2$,n,"||")
 if len(a3$) = maxL then print a3$
 n = n + 1
wend

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Rust

const FILE: &'static str = include_str!("./unixdict.txt");

fn is_ordered(s: &str) -> bool {
    let mut prev = '\x00';
    for c in s.to_lowercase().chars() {
        if c < prev {
            return false;
        }
        prev = c;
    }

    return true;
}

fn find_longest_ordered_words(dict: Vec<&str>) -> Vec<&str> {
    let mut result = Vec::new();
    let mut longest_length = 0;

    for s in dict.into_iter() {
        if is_ordered(&s) {
            let n = s.len();
            if n > longest_length {
                longest_length = n;
                result.truncate(0);
            }
            if n == longest_length {
                result.push(s);
            }
        }
    }

    return result;
}

fn main() {
    let lines = FILE.lines().collect();

    let longest_ordered = find_longest_ordered_words(lines);

    for s in longest_ordered.iter() {
        println!("{}", s.to_string());
    }
}

Scala

val wordsAll = scala.io.Source.fromURL("http://www.puzzlers.org/pub/wordlists/unixdict.txt").getLines.toSeq

/** 
 * Given a sequence of words return a sub-sequence of the 
 * words that have characters in sorted order.
 */  
def orderedWords( words:Seq[String] ) : Seq[(String)] = {

  def isOrdered( s:String ) : Boolean = 
    (s.foldLeft( (true,'@') ){ 
      case ((false,_),_) => return false
      case ((true,prev),c) => ((prev <= c),c)
    })._1

  wordsAll.filter( isOrdered(_) ).toSeq
}

val ww = orderedWords( wordsAll ).sortBy( -_.length )

println( ww.takeWhile( _.length == ww.head.length ).mkString("\n") )

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Scheme

The following implementation uses a char>=? procedure that accepts an arbitrary number of arguments. This is allowed, but not required, by R5RS, and is provided by many Scheme implementations. It has been tested under GNU Guile 1.8.8.

(define sorted-words
  (let ((port (open-input-file "unixdict.txt")))
    (let loop ((char (read-char port)) (word '()) (result '(())))
      (cond
       ((eof-object? char)
	(reverse (map (lambda (word) (apply string word)) result)))
       ((eq? #\newline char)
	(loop (read-char port) '()
	      (let ((best-length (length (car result))) (word-length (length word)))
		(cond
		 ((or (< word-length best-length) (not (apply char>=? word))) result)
		 ((> word-length best-length) (list (reverse word)))
		 (else (cons (reverse word) result))))))
       (else (loop (read-char port) (cons char word) result))))))

(map (lambda (x)
       (begin
	 (display x)
	 (newline)))
     sorted-words)

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Seed7

$ include "seed7_05.s7i";

const func boolean: isOrdered (in string: word) is func
  result
    var boolean: ordered is TRUE;
  local
    var integer: index is 0;
  begin
    for index range 1 to pred(length(word)) do
      if word[index] > word[succ(index)] then
        ordered := FALSE;
      end if;
    end for;
  end func;

const proc: write (in array string: wordList) is func
  local
    var string: word is "";
  begin
    for word range wordList do
      writeln(word);
    end for;
  end func;

const proc: main is func
  local
    var file: dictionary is STD_NULL;
    var string: word is "";
    var integer: length is 0;
    var array string: wordList is 0 times "";
  begin
    dictionary := open("unixdict.txt", "r");
    if dictionary <> STD_NULL then
      readln(dictionary, word);
      while not eof(dictionary) do
        if isOrdered(lower(word)) then
          if length(word) > length then
            length := length(word);
            wordList := [] (word);
          elsif length(word) = length then
            wordList &:= word;
          end if;
        end if;
        readln(dictionary, word);
      end while;
      close(dictionary);
    end if;
    write(wordList);
  end func;

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Sidef

var words = [[]]
var file = %f'unixdict.txt'

file.open_r(\var fh, \var err) ->
    || die "Can't open file #{file}: $#{err}"

fh.each { |line|
    line.trim!
    if (line == line.sort) {
        words[line.length] := [] << line
    }
}

say words[-1].join(' ')

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Simula

BEGIN

   BOOLEAN PROCEDURE ISORDERED(W); TEXT W;
   BEGIN
       BOOLEAN B;
       B := TRUE;
       W.SETPOS(1);
       IF W.MORE THEN
       BEGIN
           CHARACTER CURR, LAST;
           CURR := W.GETCHAR;
           WHILE W.MORE AND B DO
           BEGIN
               LAST := CURR;
               CURR := W.GETCHAR;
               B := LAST <= CURR;
           END;
       END;
       ISORDERED := B;
   END;

   REF (INFILE) INF;
   INTEGER LONGEST;
   TEXT W;

   COMMENT FIND LONGEST LENGTH;
   INF :- NEW INFILE("unixdict.txt");
   INF.OPEN(BLANKS(132));
   WHILE NOT INF.LASTITEM DO
   BEGIN
       W :- COPY(INF.IMAGE).STRIP;
       IF ISORDERED(W) THEN
           IF W.LENGTH > LONGEST THEN
               LONGEST := W.LENGTH;
       INF.INIMAGE;
   END;
   INF.CLOSE;

   COMMENT OUTPUT ORDRERED WORDS OF LONGEST LENGTH;
   INF :- NEW INFILE("unixdict.txt");
   INF.OPEN(BLANKS(132));
   WHILE NOT INF.LASTITEM DO
   BEGIN
       W :- COPY(INF.IMAGE).STRIP;
       IF W.LENGTH = LONGEST AND THEN ISORDERED(W) THEN
       BEGIN
           OUTTEXT(W);
           OUTIMAGE;
       END;
       INF.INIMAGE;
   END;
   INF.CLOSE;

END.

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

14 garbage collection(s) in 0.0 seconds.

Smalltalk

Works with: GNU Smalltalk

|file dict r t|
file := FileStream open: 'unixdict.txt' mode: FileStream read.
dict := Set new.

"load the whole dict into the set before, 'filter' later"
[ file atEnd ] whileFalse: [
  dict add: (file upTo: Character nl) ].

"find those with the sorted letters, and sort them by length"
r := ((dict 
       select: [ :w | (w asOrderedCollection sort) = (w asOrderedCollection) ] )
     asSortedCollection: [:a :b| (a size) > (b size) ] ).

"get those that have length = to the max length, and sort alphabetically"
r := (r select: [:w| (w size) = ((r at: 1) size)]) asSortedCollection.

r do: [:e| e displayNl].

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

SPL

words = #.split(#.readtext("unixdict.txt","ascii"),#.lf)
max = 0
> i, 1..#.size(words,1)
  word = words[i]
  wordb = #.array(word)
  wordbc = #.size(wordb,1)
  > j, 3..wordbc,2
    << wordb[j]<wordb[j-2]
  <
  >> j!>wordbc|wordbc<max
  ? wordbc>max, result = ""
  ? wordbc>max, max = wordbc
  result += word+#.crlf
<
#.output(result)

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Standard ML

fun isOrdered s =
  let
    fun loop (i, c) =
      let
        val c' = String.sub (s, i)
      in
        c <= c' andalso loop (i + 1, c')
      end
      handle Subscript => true
  in
    loop (0, #"\^@")
  end

fun longestOrdereds (s, prev as (len, lst)) =
  let
    val len' = size s
  in
    if len' >= len andalso isOrdered s then
      if len' = len then (len, s :: lst) else (len', [s])
    else
      prev
  end

val () = print ((String.concatWith " "
                 o #2
                 o foldr longestOrdereds (0, [])
                 o String.tokens Char.isSpace
                 o TextIO.inputAll) TextIO.stdIn ^ "\n")

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Swift

import Foundation

guard
    let url =  NSURL(string: "http://www.puzzlers.org/pub/wordlists/unixdict.txt"),
    let input = try? NSString(contentsOfURL: url,encoding: NSUTF8StringEncoding) as String
    else { exit(EXIT_FAILURE) }

let words = input.componentsSeparatedByCharactersInSet(NSCharacterSet.newlineCharacterSet())
let group: ([Int: [String]], String) -> [Int: [String]] = {
    var d = $0; let g = d[$1.characters.count] ?? []
    d[$1.characters.count] = g + [$1]
    return d
}
let ordered: ([String], String) -> [String] = {
    guard String($1.characters.sort()) == $1 else { return $0 }
    return $0 + [$1]
}

let groups = words
    .reduce([String](), combine: ordered)
    .reduce([Int: [String]](), combine: group)

guard
    let maxLength = groups.keys.maxElement(),
    let maxLengthGroup = groups[maxLength]
    else { exit(EXIT_FAILURE) }

maxLengthGroup.forEach { print($0) }

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Tcl

package require http

# Pick the ordered words (of maximal length) from a list
proc chooseOrderedWords list {
    set len 0
    foreach word $list {
	# Condition to determine whether a word is ordered; are its characters
	# in sorted order?
	if {$word eq [join [lsort [split $word ""]] ""]} {
	    if {[string length $word] > $len} {
		set len [string length $word]
		set orderedOfMaxLen {}
	    }
	    if {[string length $word] == $len} {
		lappend orderedOfMaxLen $word
	    }
	}
    }
    return $orderedOfMaxLen
}

# Get the dictionary and print the ordered words from it
set t [http::geturl "http://www.puzzlers.org/pub/wordlists/unixdict.txt"]
puts [chooseOrderedWords [http::data $t]]
http::cleanup $t

Output:

abbott accent accept access accost almost bellow billow biopsy chilly choosy choppy effort floppy glossy knotty

Transd

#lang transd

MainModule: {
_start: (lambda
    (with fs FileStream() len 0 maxlen 0 words Vector<String>()
        (open-r fs "/mnt/vault/tmp/unixdict.txt") )
        
        (for w in (read-lines fs) do
            (= len (size w))
            (if (< len maxlen) continue)
            (if (is-sorted w)
                (if (< maxlen len)
                    (clear words) (= maxlen len))
                (append words w)
        ))
        (lout words)
))

}

Output:

["abbott", "accent", "accept", "access", "accost", "almost", "bellow", "billow", "biopsy", "chilly", "choosy", "choppy", "effort", "floppy", "glossy", "knotty"]

TUSCRIPT

$$ MODE TUSCRIPT
SET data = REQUEST ("http://www.puzzlers.org/pub/wordlists/unixdict.txt")
DICT orderdwords CREATE 99999
COMPILE
LOOP word=data
 - "<%" = any token
 SET letters=STRINGS (word,":<%:")
 SET wordsignatur= ALPHA_SORT (letters)
 IF (wordsignatur==letters) THEN
  SET wordlength=LENGTH (word)
  DICT orderdwords ADD/COUNT word,num,cnt,wordlength
 ENDIF
ENDLOOP

DICT orderdwords UNLOAD words,num,cnt,wordlength
SET maxlength=MAX_LENGTH (words)
SET rtable=QUOTES (maxlength)
BUILD R_TABLE maxlength = rtable
SET index=FILTER_INDEX (wordlength,maxlength,-)
SET longestwords=SELECT (words,#index)
PRINT num," ordered words - max length is ",maxlength,":"

LOOP n,w=longestwords
SET n=CONCAT (n,"."), n=CENTER(n,4)
PRINT n,w
ENDLOOP
ENDCOMPILE

Output:

422 ordered words - max length is 6:
 1. abbott
 2. accent
 3. accept
 4. access
 5. accost
 6. almost
 7. bellow
 8. billow
 9. biopsy
10. chilly
11. choosy
12. choppy
13. effort
14. floppy
15. glossy
16. knotty

Ursala

#import std

#show+

main = leql@bh$^ eql|= (ordered lleq)*~ unixdict_dot_txt

leql is a binary predicate testing a pair of lists for less or equal length
eql tests for equal length
lleq tests for lexically less or equal relatedness between characters or strings
ordered takes a binary predicate to a predicate operating on a list, which tests whether every pair of consecutive items is related by the binary predicate
postfix operator *~ turns a predicate into a list filtering function, deleting any item not satisfying it
postfix operator |= turns an equivalance relational predicate into function that partitions a list into a list of equivalence classes
postfix operator $^ turns a predicate into a function that searches a list for the maximum member with respect to it
postfix operator @bh makes its operand function apply to the pair of heads of a pair of lists
loading a file unixdict.txt into a list of strings is implied by using its name as an identifier and supplying it to the compiler in a command line parameter

output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

VBA

Public Sub orderedwords(fname As String)
 ' find ordered words in dict file that have the longest word length
 ' fname is the name of the input file
 ' the words are printed in the immediate window
 ' this subroutine uses boolean function IsOrdered
 
Dim word As String          'word to be tested
Dim l As Integer            'length of word
Dim wordlength As Integer   'current longest word length
Dim orderedword() As String 'dynamic array holding the ordered words with the current longest word length
Dim wordsfound As Integer   'length of the array orderedword()

On Error GoTo NotFound      'catch incorrect/missing file name
Open fname For Input As #1
On Error GoTo 0

'initialize
wordsfound = 0
wordlength = 0

'process file line per line
While Not EOF(1)
  Line Input #1, word
  If IsOrdered(word) Then    'found one, is it equal to or longer than current word length?
    l = Len(word)
    If l >= wordlength Then  'yes, so add to list or start a new list
      If l > wordlength Then 'it's longer, we must start a new list
        wordsfound = 1
        wordlength = l
      Else                   'equal length, increase the list size
        wordsfound = wordsfound + 1
      End If
      'add the word to the list
      ReDim Preserve orderedword(wordsfound)
      orderedword(wordsfound) = word
    End If
  End If
Wend
Close #1

'print the list
Debug.Print "Found"; wordsfound; "ordered words of length"; wordlength
For i = 1 To wordsfound
  Debug.Print orderedword(i)
Next
Exit Sub

NotFound:
  debug.print "Error: Cannot find or open file """ & fname & """!"
End Sub



Public Function IsOrdered(someWord As String) As Boolean
'true if letters in word are in ascending (ascii) sequence

Dim l As Integer         'length of someWord
Dim wordLcase As String  'the word in lower case
Dim ascStart As Integer  'ascii code of first char
Dim asc2 As Integer      'ascii code of next char

wordLcase = LCase(someWord)  'convert to lower case
l = Len(someWord)
IsOrdered = True
If l > 0 Then            'this skips empty string - it is considered ordered...
  ascStart = Asc(Left$(wordLcase, 1))
  For i = 2 To l
    asc2 = Asc(Mid$(wordLcase, i, 1))
    If asc2 < ascStart Then 'failure!
      IsOrdered = False
      Exit Function
    End If
    ascStart = asc2
  Next i
End If
End Function

Results:

OrderedWords("unixdict.txt")
Found 16 ordered words of length 6 
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

VBScript

Note: The input file is in the same folder as the script.

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set infile = objFSO.OpenTextFile(objFSO.GetParentFolderName(WScript.ScriptFullName) & "\" &_
			"unixdict.txt",1)
list = ""
length = 0

Do Until inFile.AtEndOfStream
	line = infile.ReadLine
	If IsOrdered(line) Then
		If Len(line) > length Then
			length = Len(line)
			list = line & vbCrLf
		ElseIf Len(line) = length Then
			list = list & line & vbCrLf
		End If
	End If
Loop

WScript.StdOut.Write list

Function IsOrdered(word)
	IsOrdered = True
	prev_val = 0
	For i = 1 To Len(word)
		If i = 1 Then
			prev_val = Asc(Mid(word,i,1))
		ElseIf Asc(Mid(word,i,1)) >= prev_val Then
			prev_val = Asc(Mid(word,i,1))
		Else
			IsOrdered = False
			Exit For
		End If
	Next
End Function

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

Vedit macro language

File_Open("unixdict.txt", BROWSE)
#1 = 2                                  // length of longest word found
Repeat (ALL) {
    #2 = EOL_Pos-Cur_Pos                // length of this word
    if (#2 >= #1) {
        #3 = 1                          // flag: is ordered word
        Char(1)
        While (!At_EOL) {
            if (Cur_Char < Cur_Char(-1)) {
                #3 = 0                  // not an ordered word
                break
            }
            Char(1)
        }
        if (#3) {                       // ordered word found
            if (#2 > #1) {              // new longer word found
                #1 = #2
                Reg_Empty(10)           // clear list
            }
            BOL Reg_Copy(10,1,APPEND)   // add word to list
        }
    }
    Line(1,ERRBREAK)                    // next word
}
Buf_Quit(OK)                            // close file
Reg_Type(10)                            // display results

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

V (Vlang)

Translation of: Wren

fn main() {
    words := os.read_file("./unixdict.txt") or {println(err) exit(-1)}.split_into_lines()
	mut longest_len := 0
	mut longest := []string{}
	mut u_word := []u8{}
	for word in words {
		for chars in word {u_word << chars}
		u_word.sort()
		if word.len > longest_len {
			if word == u_word.bytestr() {
				longest_len = word.len
				longest.clear()
				longest << word
			}
		} 
		else if word.len == longest_len {
			if word == u_word.bytestr() {longest << word}
		}
		u_word.clear()
	}
	println("The ${longest.len} ordered words with the longest length (${longest_len}) are:")
	print(longest.join("\n"))
}

Output:

The 16 ordered words with the longest length (6) are:
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knott

Wren

Library: Wren-sort

import "io" for File
import "./sort" for Sort

var words = File.read("unixdict.txt").split("\n")
var longestLen = 0 
var longest = []
for (word in words) {
    if (word.count > longestLen) {
        if (Sort.isSorted(word.toList)) {
            longestLen = word.count
            longest.clear()
            longest.add(word)
        }
    } else if (word.count == longestLen) {
        if (Sort.isSorted(word.toList)) longest.add(word)
    }
}
System.print("The %(longest.count) ordered words with the longest length (%(longestLen)) are:")
System.print(longest.join("\n"))

Output:

The 16 ordered words with the longest length (6) are:
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

XPL0

string  0;              \use zero-terminated strings
int     MaxLen, Pass, I, Ch, Ch0;
char    Word(25);
def     LF=$0A, CR=$0D, EOF=$1A;
[FSet(FOpen("unixdict.txt", 0), ^I);
MaxLen:= 0;
for Pass:= 1 to 2 do
        [OpenI(3);
        repeat  I:= 0;  Ch0:= 0;
                loop    [repeat Ch:= ChIn(3) until Ch # CR;  \remove possible CR
                        if Ch=LF or Ch=EOF then
                                [if I > MaxLen then MaxLen:= I;
                                if I=MaxLen & Pass=2 then
                                        [Word(I):= 0;  Text(0, Word);  CrLf(0)];
                                quit;
                                ];
                        Word(I):= Ch;
                        if Ch < Ch0 then
                                [repeat Ch:= ChIn(3) until Ch=LF or Ch=EOF;
                                quit;
                                ];
                        Ch0:= Ch;
                        I:= I+1;
                        ];
        until   Ch = EOF;
        ];
]

Output:

abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty

zkl

One pass, dictionary stays on disk:

var words=L(), sz=0;  // some state
fcn isLex(word){ word.reduce(fcn(p,c){ (p<=c) and c or T(Void.Stop,False) }) }
File("dict.txt").pump(Void,fcn(w){
   w=w.strip();   // get rid of newline
   if(isLex(w)){ n:=w.len(); 
      if(n>sz){ words.clear(w); sz=n } 
      else if(n==sz) words.append(w)
   }
})
println("Num words: %d, all size %d\n".fmt(words.len(),sz));
words.pump(Console.println);

Or, reading dictionary into memory:

fcn isLex(word){ word.reduce(fcn(p,c){ (p<=c) and c or T(Void.Stop,False) }) }
lwords:=File("dict.txt").readln(*).apply("strip").filter(isLex);
max:=lwords.reduce(fcn(n,w){ w.len()>n and w.len() or n },0);
lwords=lwords.filter(fcn(w,n){ w.len()==n },max);
println("Num words: %d, all size %d\n".fmt(lwords.len(),max));
words.pump(Console.println);

Output:

Num words: 16, all size 6
abbott
accent
accept
access
accost
almost
bellow
billow
biopsy
chilly
choosy
choppy
effort
floppy
glossy
knotty