Programming Puzzle 2 - Another Simple Loop

[Tom Cone Jr]

Puzzles and Problems

Beginning Xbasic Programming

Puzzle 2 - Another simple loop



Feeling a bit "loopy" after puzzle #1 ?  Here's another.

Write an xbasic script that:

a) prompts the user to supply (input) a character
   string, longer than 10 characters.

b) checks the length of the input string, and displays
   an error message to the user if his string is
   too short - then end your script

c) if the input string of characters is long enough your
   script should then "reverse" the input string and
   display the result in a message box for the user.

   i.e.  if the user entered:   Tom Cone, Jr.

         the result your script should display is:

                                .rJ ,enoC moT


Your code must use a loop structure.  You may 
not use or sort an array.  

[ It's been brought to my attention that xbasic includes
a function that will reverse character strings for you.  Please
try to solve the puzzle without using that function.  If you're
curious it's called *reverse().   Let's do some heavy
lifting for ourselves, rather than use the built-in function
in this instance. ]

You must preserve punctuation, blank spaces, and 
the case of each letter from the original string.

Liberal use of comments is expected.  Others will
be reading your code.  Help them understand what
your script is doing!

Have fun!

ps.  Bonus points will be awarded if your script
     can also "reconstruct" the original string
     from the "reversed" string.

[Tim Kiebert]

[ It's been brought to my attention that xbasic includes
a function that will reverse character strings for you.  Please
try to solve the puzzle without using that function.  If you're
curious it's called *reverse().   Let's do some heavy
lifting for ourselves, rather than use the built-in function
in this instance. ]

Drat, I was going to be a smart *ss and post a script that used *reverse()

for i = 1 to 1
result_vlc = *reverse(input_vlc)
next i

[MikeC]

Here is probably the easiest method that a user can learn....

dim vchar_str as C
vchar_str = "Tom Cone, Jr."
dim vnum_char as N
vnum_char = len(vchar_str)'gives us the total number of characters in the string

if vnum_char < 11 'has to be more than 10 characters so anything under 11 is invalid
  msgbox("ERROR!!","Your character string must have more than 10 characters.")
  end
end if

dim vReversed as C
vReversed="" 'always a good idea to make certain the variable starts out as nothing
dim x as N  
x=0
' x is used in the following substr function to decrement the total number of characters

for i = 1 to vnum_char
  vReversed =vReversed + substr(vchar_str,vnum_char-x,1)
  x = x + 1
next

msgbox("Reversal", "Your character string has been reversed to:" + crlf(2) + vReversed)

[GGandhi]

second puzzle
conditions
ask user for input longer than 10 characters if not inform and end
if ok then reverse the string without using builtin xbasic function.
while i am in no way proficient in xbaxsic, here is my attempt

dim vInput_String as c '
dim xInput_string as n 'number place holder for length
dim vReversed_string as c ' 
dim i as n 'counter variable
dim vOriginal_string as c '

vInput_String=ui_get_text("Input String","Enter any string not less than 10 characters: ")
xInput_string=len(vInput_string)
if xInput_string < 11 'must meet the length criteria
	msgbox("Error", "You must enter 10 or more characters")
	end 
	end if
	
'vReversed_string
vReversed_string = ""
for i = xInput_string to 1 step -1 ' count backwards
	vReversed_string=vReversed_string + (substr(vInput_string,i,1))
	next
	msgbox("Reversed String", "Your character string reversed:     " + vReversed_String)
'reversed vReversed_string - back to the original
vOriginal_string = ""
for i = xInput_string to 1 step -1 ' count backwards
	vOriginal_string = vOriginal_string + (substr(vReversed_String,i,1))
	next
	msgbox("Original String", "Your reversed string reverted to original:     " + vOriginal_String)

gandhi

ps: formatting as per mr tom cone jr- thanks

[Ray in Capetown]

for i = 1 to vnum_char
vReversed =vReversed + substr(vchar_str,vnum_char-x,1)
x = x + 1
next

Chirp, eliminate all reference to variable x, using one simpler line in the loop

for i = vnum_char to i step -1
  vReversed =vReversed + substr(vchar_str,i,1)
next

[GGandhi]

Orignally I posted an answer to the puzzle- this one just changed to a function of the reversing scheme
sorry for double posting

gandhi

'Date Created: 04-Jun-2011 06:28:39 AM
'Last Updated: 04-Jun-2011 06:28:39 AM
'Created By  : Govindan Gandhi
'Updated By  : Govindan Gandhi
FUNCTION reverse_string AS C (input_string AS C )
	dim i as n
	dim length as n
	length = len(input_string)
	for i = length to 1 step -1
		reverse_string=reverse_string+(substr(input_string,i,1))
		next
END FUNCTION
dim vInput_string as c
dim vReversed_string as c
dim vOriginal_string as c

vInput_string = ui_get_text("Enter string","Please enter a string of 10 characters or more:")
if len(vInput_string)<11 then
    msgbox("error","You must enter 10 characters or more!")
    end
end if
vreversed_string=reverse_string(vInput_string)
msgbox("Reversed string", "Here is your string reversed:   " + vReversed_string)
vOriginal_string=reverse_string(vreversed_string)
msgbox("Back to original", "Your original string:    " + vOriginal_string)

[Tom Cone Jr]

Nice work gents.

You're as "loopy" as me!

Mike, Ray's comment is a good one. Your approach requires Alpha to increment both the loop counter ( i ) and the character position counter ( x ). Notice that Govindan's approach uses the loop counter itself as a position counter of sorts. The result - only one variable is being changed as the loop iterates through the characters. I've been down this road myself a few times. I've learned that it pays to simplify when possible. Debugging scripts with multi-variable "counters" is tedious and error prone, at least that's been my experience.

Govindan, you get bonus points for "reconstructing" the original string. Good work.

Thanks to all for your submittals.

If others have questions about these scripts please post here. I'm retreating to the puzzle shack to start cooking up another one.

-- tom

[MikeC]

Your approach requires Alpha to increment both the loop counter ( i ) and the character position counter ( x ).

Exactly!! I just wanted to start it out using the most straight-forward method that a new user could more easily follow is all....and is the reason I added spaces between the pieces of script for readability.

[Tom Cone Jr]

Thanks, Mike.

-- t

[RobPolley]

I'm struggling to learn programming, with xbasic. I'd like to copy & paste these into Alpha to see them run, but I'm not sure where; would the code go onto a form?

Thank you.

--Rob

[aschone]

I'm struggling to learn programming, with xbasic. I'd like to copy & paste these into Alpha to see them run, but I'm not sure where; would the code go onto a form?

Thank you.

--Rob

In the "control panel" there is a "Code" tab. With the "Code" selected you have the option to create new script. You can paste the code into a new script then save the script with any name you wish.
For an Xbasic Tutorial go here - V10 Help file
Under the "Contents" select "Tutorials" then "Learning Xbasic"

[jeb richardson]

dim input as C
dim reverse_input as C
dim reconstruct_input as C
dim qx as N
dim length as N
input=ui_get_text("String Please","Please enter a string that contains 10+ characters:")
length=len(input)
IF length <11
	ui_msg_box("Error","Your string must contain 10+ characters; nothing less!")
	end
END IF
reverse_input=""
FOR qx = length TO 1 step -1
	reverse_input=reverse_input+(substr(input, qx, 1))
next
msgbox("Reversed","Here is your string reversed: "+reverse_input)
reconstruct_input=""
FOR qx = length TO 1 step -1
	reconstruct_input=reconstruct_input+(substr(reverse_input, qx, 1))
next
msgbox("Reversed, Reversed", "Here is your sting reversed,reversed or back to normal: "+reconstruct_input)

[Tom Cone Jr]

Jeb, very nice.

have you discovered how to "export" a saved script? And then how to "import" a previously exported script?

-- tom

[steveharris]

Tom, and everyone who contributed to these discussions.

Obviously, I've come very late to this party, so I won't post any solutions. But I am working through each puzzle, trying to solve it first and then reading the thread to see what others have done. This is very useful; I just want to say "thanks" to all of you for the work. It really helps this Alpha Five newbie.

sh

[Tom Cone Jr]

Welcome to the party. Don't get frustrated if your wheels start spinning and you can't get traction. Post questions here, or drop me a private message using the message facility the board provides. -- tom

[waresport]

I am new,so i won't post any solutions before i get a comprehensive understanding of this forum.

[Tom Cone Jr]

Lily, welcome to the message board, and to this forum. This forum provides a series of puzzles that one is asked to solve using only xbasic. It's intended as a sort of teaching / learning experience. So dig in, try your hand, and let us know where you get stuck. By all means show us your solution(s).