Procedure.s TrimString(s1$,s2$)
Protected fs
while left(s1$,len(s2$))=s2$ or right(s1$,len(s2$))=s2$
if left(s1$,len(s2$))=s2$
s1$=right(s1$,len(s1$)-len(s2$))
endif
if right(s1$,len(s2$))=s2$
s1$=left(s1$,len(s1$)-len(s2$))
endif
wend
ProcedureReturn s1$
EndProcedure

; cw() <- is short for consolewrite()

s1$ ="dog cat monkey dog horse dog" ;<- dog on both ends
s2$ ="dog"
s1$ =TrimString(s1$,s2$)
cw(s1$) ;>" cat monkey dog horse " ;<- 0x20 on both ends
s2$ ="cat"
s1$ =TrimString(s1$,s2$)
cw(s1$) ;>" cat monkey dog horse " ;<- 0x20 on both ends

; Input string: "dog cat monkey dog horse dog"
; Strings that need to be trimmed from each end: { "dog", "cat" }

; Note: he says: 'Strings that need to be trimmed from each end'
; not that the Input string should be trimmed of 0x20

; that's probably obvious... but i thought i read a comment that
; the Input string should be trimmed of 0x20 (whitespaces)

; language PureBasic...

Chris Maunder... without having to think too much (and thus stress my feeble brain)

include 'win32a.inc'
format PE console 4.0
entry start
;*********************************************
section '.data' data readable writeable

_s db '%s',13,0

i_string db 'dog cat monkey dog horse dog'
o_string db 21 dup(0)

;*********************************************
section '.text' code readable executable
;*********************************************
start: ;fasm_dogcat.fasm

mov ebx,3
xor ecx,ecx
above:
mov eax,dword[i_string+ebx+ecx*4]
mov dword[o_string+ecx*4],eax
inc ecx
cmp ecx,5
jnz above
mov ax,word[i_string+ebx+ecx*4]
mov word[o_string+ecx*4],ax

cinvoke printf,_s,o_string

; >"C:\_sys\temp\shell.exe"
;$20,'cat monkey dog horse',$20,0
; >Exit code: 0
;*********************************************
invoke ExitProcess,0
;***********************************************
section '.idata' data import readable writeable
library kernel32,'kernel32.dll',\
user32,'user32.dll',\
msvcrt,'msvcrt.dll'
include 'api\kernel32.inc'
include 'api\user32.inc'
import msvcrt,\
printf,'printf'
;***********************************************

brianO