In pseudocode the program works as follows:
open file for reading (input)
open file for writing (ouput)
while not at the end of the file:
read next word in the input file
reverse the word
write the reversed word into the output file
close both files
I tested this program using a dictionary file of over 100000 English words and the output can be seen below:
Full source code follows:
REM T Street
REM 2014-12-12
REM reads each word from a file, reverses it and
REM then dumps it back into a new file
ON ERROR ERROR 0, "Oh dear, something went wrong "+REPORT$
REM filenames
Filename_input$ = "<put filename here>.txt" : REM change this
Filename_output$ = "reversed.txt"
REM carriage return line feed
CRLF$ = CHR$(13)+CHR$(10)
REM open up the file for reading
FileIn% = OPENUP( Filename_input$ )
FileOut% = OPENOUT( Filename_output$ )
REM some helpful comments
PRINT "Reading from " Filename_input$
PRINT "Reversing words..."
REM the M A I N L O O P
REM ---------------------
WHILE NOT(EOF#FileIn%)
REM read in each word
INPUT#FileIn%, word$
REM reverse it
reversedWord$ = FN_reverseMe( word$ )
REM write to new file
PRINT#FileOut%, reversedWord$+CRLF$
ENDWHILE
REM now finished with every word
REM so close both the files
CLOSE#FileIn%
CLOSE#FileOut%
REM finish up
PRINT "Done - saved to " Filename_output$
STOP
DEFFN_reverseMe( aString$ )
REM reverses the string passed as parameter
REM and returns it
LOCAL i%
LOCAL myNewString$
REM step backwards through the string
REM look at each character in sequence
FOR i% = LEN(aString$) TO 1 STEP -1
REM add on the current character
myNewString$ += MID$( aString$, i%, 1)
NEXT
= myNewString$