Re: string sorting

 BBS: Inland Empire Archive
Date: 11-21-92 (11:21)             Number: 375
From: DIK COATES                   Refer#: NONE
  To: JOHN GALLAS                   Recvd: NO  
Subj: Re: string sorting             Conf: (2) Quik_Bas

>>>> QUOTING Joe Clark to John Gallas <<<<

 JC> If you are looking for a basic sorting routine, then the
 JC> fastest that I have used is the "SHELL-METZNER SORT"

Enclosed for your edification:

'***************************************************** SUBPROGRAM Sortshell.1
'
'   Procedure uses the Shell-Metzger algorithm for sorting an array of string
'   variables.  Adapted from an article by Donald Shell.  This sorting
'   algorithm is extremely efficient for sorting small and medium sized
'   arrays.
'
'   PARAMETERS: col0% = number of elements in the string array array$()
'               array$() = string variable array to be sorted.
'   RETURNS:    array$() = sorted string variable array
'
'   REV:        88-04-01
'
SUB Sortshell.1 (col0%, array$())
    col1% = col0%

    WHILE col1% <> 0
        col1% = col1% \ 2
        col2% = col0% - col1%

        FOR count% = 1 TO col2%
            col3% = count%
sort1:
            col4% = col3% + col1%

            IF array$(col3%) <= array$(col4%) THEN
                GOTO sort2
            ELSE
                SWAP array$(col3%), array$(col4%)
                col3% = col3% - col1%
            END IF

            IF col3% > 0 THEN
                GOTO sort1
            END IF
sort2:
        NEXT count%
    WEND
END SUB


Was cooked from original assembly code from IBM mainframe back when
I was young and foolish...It is fast, but for random generated strings.
If the list is partially sorted (or only 1 element out of place, as
common for database stuff, then old bubble sort is by far the fastest)

Regards Dik

... Vote Conservative or I'll shoot your dog. -Dik
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