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Thread: Programming Puzzle 2 - Another Simple Loop

  1. #1
    "Certified" Alphaholic
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    Tom Cone Jr
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    Default Programming Puzzle 2 - Another Simple Loop

    Code:
    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.
    Last edited by Tom Cone Jr; 06-03-2011 at 08:32 PM. Reason: Oops!

  2. #2
    "Certified" Alphaholic Tim Kiebert's Avatar
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    Quote Originally Posted by Tom Cone Jr View Post
    Code:
    [ 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()

    Code:
    for i = 1 to 1
    result_vlc = *reverse(input_vlc)
    next i
    Last edited by Tim Kiebert; 06-03-2011 at 08:54 PM.
    Tim Kiebert
    Geelong Citrus Packers
    A complex system that does not work is invariably found to have evolved from a simpler system that worked just fine.

  3. #3
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    Default Re: Programming Puzzle 2 - Another Simple Loop

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

    Code:
    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)
    Mike
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    It is only when we forget all our learning that we begin to know.
    It's not what you look at that matters, it's what you see.
    Henry David Thoreau
    __________________________________________




  4. #4
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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

    Code:
    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
    Last edited by GGandhi; 06-04-2011 at 06:17 AM. Reason: edited to include additional code for reverting the reversed string

  5. #5
    "Certified" Alphaholic Ray in Capetown's Avatar
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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
    Code:
    for i = vnum_char to i step -1
      vReversed =vReversed + substr(vchar_str,i,1)
    next
    Last edited by Ray in Capetown; 06-04-2011 at 06:03 AM.

  6. #6
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    Default Re: Programming Puzzle 2 - Another Simple Loop

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

    gandhi

    Code:
    '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)

  7. #7
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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

  8. #8
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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.
    Mike
    __________________________________________
    It is only when we forget all our learning that we begin to know.
    It's not what you look at that matters, it's what you see.
    Henry David Thoreau
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  9. #9
    "Certified" Alphaholic
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    Thanks, Mike.

    -- t

  10. #10
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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

  11. #11
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    Quote Originally Posted by RobPolley View Post
    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"

  12. #12
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    Code:
    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)
    Last edited by jeb richardson; 08-03-2011 at 04:04 PM.

  13. #13
    "Certified" Alphaholic
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    Jeb, very nice.

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

    -- tom

  14. #14
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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

  15. #15
    "Certified" Alphaholic
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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

  16. #16
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    Default Re: Programming Puzzle 2 - Another Simple Loop

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

  17. #17
    "Certified" Alphaholic
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    Default Re: Programming Puzzle 2 - Another Simple Loop

    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).

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