Increment a string - dohhhh!

[Dale Hubbard]

Hi,

I've been sitting in front of PB35 for an hour now, scratching my head...

All I want to do is start with a string like "AAAA" - and increment
it so that I get

AAAA
AAAB
... (skipped for obvious brevity)
AABA
AABB
... (skip)
ZZZZ

In simple terms, "AAAA" thru "ZZZZ" -- all combinations.

Can some kind person put me out of my misery -- I did search here
and found a subroutine which I couldn't fathom out...

Thanks!

[Mel Bishop]

for a = 65 to 90
for b = 65 to 90
for c = 65 to 90
for d = 65 to 90
'
TextString$ = chr$(a) + chr$(b) + chr$(c) + chr$(d)
'
do something with the text string
'
next d
next c
next b 
next a

This what you had in mind?


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[This message has been edited by Mel Bishop (edited September 13, 2005).]

[Dale Hubbard]

You are so kind.

Exactly what I needed. Just had a complete blank on it.

Thanks again!

[Jim Martin]

Try this:

Assuming an input string "InputString$", a lower ASCII value for
string values LowerLimit% and an upper value UpperLimit%,
declare the following variables as shared:

k%, w%, LowerLimit%, UpperLimit%, StartLocation%, FinalLocation%,
WorkingString$

Set the following values:

LowerLimit% = 65
UpperLimit% = 90 'Upper case A to Z, modify as you will

WorkingString$ = "X" + InputString$ + "X"
k% = Len(InputString$)
StartLocation% = k% + 1
w% = StartLocation%
FinalLocation% = w%

Now call the subroutine ModifyString. When it exits, WorkingString$
will be modified by one increment, except that you need to strip off
the leading and trailing character (which were inserted to avoid
zero-length right and left fragments). If FinalLocation% is zero,
the sequence of modifications is complete. After each run of
ModifyString, do NOT change the values assigned above until you want
to deal with a new string.


SUB ModifyString

ModificationComplete% = 0

Do While (ModificationComplete% = 0)

RightFragment$ = Right$(WorkingString$,(w% - 1))
MiddleFragment$ = Mid$(WorkingString$,w%,1)
LeftFragment$ = Left$(WorkingString$,(k% + 2 - w%)

x% = asc(MiddleFragment$)
incr x%

If (x% > UpperLimit%) then
x% = LowerLimit%
decr w%
ModificationComplete% = 0
Else
If (ModificationComplete% = 0) then
FinalLocation% = w%
w% = StartLocation%
End if
ModificationComplete% = 255
End If

MiddleFragment$ = Chr$(x%)

WorkingString$ = LeftFragment$ + MiddleFragment$ + RightFragment$

Wend

END SUB

Jim Martin


------------------

[Donald Darden]

Here is a very simple technique for any string length:

Oops! Left out a very important increment step:

DO
   FOR a = LEN(aa$) TO 1 STEP -1
     MID$(aa$, a) = CHR$(ASC(aa$, a) + 1)
     IF MID$(aa$, a, 1) <="Z" THEN EXIT FOR
     MID$(aa$, a) = "A"
   NEXT
   IF a = 0 THEN EXIT DO
   'Do what you want with the string here
LOOP

This might be slightly faster:

DO
   FOR a = LEN(aa$) TO 1 STEP -1
     b = ASC(aa$, a)
     INCR b
     IF b > ASC("Z") THEN b = ASC("A")
     MID$(aa$, a) = CHR$(b)
     IF b > ASC("A") THEN EXIT FOR
   NEXT
   IF a = 0 THEN EXIT DO
   'Do what you want with the string here
LOOP

------------------
Old Navy Chief, Systems Engineer, Systems Analyst, now semi-retired

[This message has been edited by Donald Darden (edited September 19, 2005).]

[Dale Hubbard]

Thanks again for such fantastic help. I'm going to buy the latest versions of PBCC and PBWin on the strength of this great forum!

Cheers!