Not the normal looping question...

This is a discussion on Not the normal looping question... within the C++ Programming forums, part of the General Programming Boards category; I have a situation, I'm hoping someone has seen before... My program runs fine. (That's a first!--LOL) The program is ...

  1. #1
    JKI
    JKI is offline
    Registered User JKI's Avatar
    Join Date
    Sep 2003
    Posts
    19

    Not the normal looping question...

    I have a situation, I'm hoping someone has seen before...

    My program runs fine. (That's a first!--LOL)

    The program is essentially a class to handle an inventory file. It has a menu with four options to display data by four distinct items. Each is a member function of the class. The menu is also a member of the class. And they all work fine.

    Here's the problem:

    In attempting to loop the progam until the exit option is chosen, I have tried looping it in "main" by instantiating the class and calling the menu in a loop... I have also tried just re-calling the menu after the last function called finishes displaying... all to no avail.

    What happens is, everything works fine the first time thru, but upon the user changing menu choices to search via a different piece of data... all searches come back "not found."

    I initially thought I was losing my indexing arrays, or there was junk in the stream when the user enters search items, but neither is true. I "cout" the arrays and all needed variables within the functions to debug it, but they are all 100% correct.

    So... my current "stupid question of the day" is:

    Has anyone seen anything like this? I can post code, but it's long and ugly, and is running fine on it's own... only when a user changes menu choices does it choke on me.

    Thoughts?
    "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Einstein

  2. #2
    Wen Resu
    Join Date
    May 2003
    Posts
    219
    post code, least relevant parts.

  3. #3
    Carnivore ('-'v) Hunter2's Avatar
    Join Date
    May 2002
    Posts
    2,879
    >>My program runs fine.
    >>When a user changes menu choices it chokes on me.
    When in the future you become a billionaire from your prospering software company, remind me not to buy any of your programs!

    How is the choice stored, and how do you do your "search", and are you dynamically allocating/deleting anything, are you setting pointers to NULL (or 0)? Relevant code?

    In short: What does the program do, and how does it (try to) do what it does? Help us help you
    Just Google It. √

    (\ /)
    ( . .)
    c(")(") This is bunny. Copy and paste bunny into your signature to help him gain world domination.

  4. #4
    verbose cat
    Join Date
    Jun 2003
    Posts
    209

    Re: Not the normal looping question...

    Originally posted by JKI
    The program is essentially a class to handle an inventory file. It has a menu with four options to display data by four distinct items. Each is a member function of the class. The menu is also a member of the class. And they all work fine.

    Here's the problem:

    What happens is, everything works fine the first time thru, but upon the user changing menu choices to search via a different piece of data... all searches come back "not found."

    Does the class do a search through the actual file when the user puts in a search item or is the file being loaded into memory first?

    If searching through the actual file, when the user goes to do another search, are you resetting the file pointer to the beginning of the file, or is the search taking place from the point in the file where the last match was made?

    Hope this helps

    -jEssYcAt

  5. #5
    JKI
    JKI is offline
    Registered User JKI's Avatar
    Join Date
    Sep 2003
    Posts
    19
    Okay... I warn you, the code is verbose and not pretty. LOL.

    Also, the test file must be present (inventory.dat).


    You can search by Inventory Number: 000, 111, 222, etc.

    Or, by Inventory Name: ones, twos, threes, etc.

    Inventory Codes are: ONE, TWO, THR, etc.

    This should be enough to see where I'm screwing up.


    I didn't mean to be vague, but, because the code works without any loops... I didn't think it was needed. This version of the program has the looping done by caling the menu at the end of each display function.

    Also, it "couts" all the arrays and searchable variables in each function, so you can see what they hold. (this is for my debugging only).

    As for your questions:

    The indexing arrays are loaded within the constructor. They consist of a sequential number (so I can position the seekg pointer within the binary file.) and the searchable item. These arrays are dynamically allocated.

    They are each sorted and searched for user specified record and output from the "target," on (ascending).

    The actual DAT file is opened before, and closed after each display. Yes, I reposition the pointer using seekg and my indexing array (location * record size).

    If I change the loop, to a "for" or "while" (either unending or incremented) in main (and remove the menu call at the end of each display function)... it does the same thing. Looks to me like the correct data is there, but something is definately wrong. (Aside from my sloppy coding!).

    Thanks:: Jazz
    Attached Files Attached Files
    Last edited by JKI; 10-17-2003 at 04:41 PM.
    "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Einstein

  6. #6
    JKI
    JKI is offline
    Registered User JKI's Avatar
    Join Date
    Sep 2003
    Posts
    19
    Sorry... it wouldn't let me upload a DAT file.

    Here it is, renamed TXT.

    (It needs to be named "inventory.dat" for the program to run.)

    I hope this works... Windows was not happy renaming this file.
    Attached Files Attached Files
    "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Einstein

  7. #7
    Carnivore ('-'v) Hunter2's Avatar
    Join Date
    May 2002
    Posts
    2,879
    I haven't actually checked your code yet since I need to leave right now, but a quick suggestion: Are you just reading until eof() and are you using the same ifstream/fstream object to do the reading each time? If so, you need to call clear() after reading the file through, otherwise the EOF error flag will still be there when you try to open the file again.

    Hope this helps!
    Just Google It. √

    (\ /)
    ( . .)
    c(")(") This is bunny. Copy and paste bunny into your signature to help him gain world domination.

  8. #8
    JKI
    JKI is offline
    Registered User JKI's Avatar
    Join Date
    Sep 2003
    Posts
    19
    Originally posted by Hunter2
    I haven't actually checked your code yet since I need to leave right now, but a quick suggestion: Are you just reading until eof() and are you using the same ifstream/fstream object to do the reading each time? If so, you need to call clear() after reading the file through, otherwise the EOF error flag will still be there when you try to open the file again.

    Hope this helps!
    No, it is not until EOF. The indexing array is sorted, searched, and then I print all records (>=) the specified target, if found. (using seekg and the record # * record size--it's a "fixed length" binary file--so it moves around the file as needed.)

    Yes it is the same stream, but I thought I adequately positioned the clear(), right after the file is opened. It never makes it to this point, as the file is opened only upon "finding" a match in the indexing arrays. Odd part is, I see what the arrays have, and what the search target is, and they match... I just don't understand how the functions are working on their own, but by attempting to change the search criteria in the loop is throwing it off... especially, when the very same search (when not looped) will find it.

    I'm missing something very simple I'm sure, but at this point... I'm blind to the logic as I know what it should be doing... but isn't. LOL.
    "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Einstein

  9. #9
    Super Moderator VirtualAce's Avatar
    Join Date
    Aug 2001
    Posts
    9,590
    Normally in C++ this means that the data in your array has been corrupted via a wild pointer or something. Perhaps you deleted something and are trying to re-access it or perhaps you are overrunning your array bounds by mistake. Put in cout or printf() statements at all points where data is manipulated in your code as well as code to pause the system. Then when the code executes the first time, examine the output. Try it again and examine the output the second time. You should be able to track down the bug.

    My guess is you have either a memory leak or an array problem which is messing with other pointers in the code.

  10. #10
    JKI
    JKI is offline
    Registered User JKI's Avatar
    Join Date
    Sep 2003
    Posts
    19
    I already implemented what you have suggested. (Each function shows--outputs--what was passed to it, and the arrays are displayed after being sorted.)

    The information contained in them are 100% correct.
    Last edited by JKI; 10-18-2003 at 07:23 AM.
    "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Einstein

  11. #11
    Super Moderator VirtualAce's Avatar
    Join Date
    Aug 2001
    Posts
    9,590
    Hmm...very odd.

    Will look into it.

  12. #12
    JKI
    JKI is offline
    Registered User JKI's Avatar
    Join Date
    Sep 2003
    Posts
    19
    Originally posted by Bubba
    Hmm...very odd.

    Will look into it.
    I appreciate everyone having taken the time... it's baffling me still.

    (NOT Too mention FRUSTRATING me still! LOL.)

    If you "run" the program, and that DAT (test file) doesn't work for you... drop word and I can shoot a good copy via email for anyone interested. When I renamed it... I wasn't sure if it stayed correctly formatted.

    ::Jazz
    "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Einstein

  13. #13
    Carnivore ('-'v) Hunter2's Avatar
    Join Date
    May 2002
    Posts
    2,879
    Mmm, yummy. I stuck it in MSVC and ran it; the moment it started, I got a debug assertion error. Running throught the debugger, it gets an access violation somewhere in the Inventory constructor (but doesn't crash because MSVC pads arrays (?) when debugging). When Inventory's constructor ends, a function gets called (by MSVC?) to check the memory and see if the padding bytes got changed, which they did I suppose, because that's where it threw an error.

    So in short: Take a look at the constructor, make sure you're not overrunning your array bounds as Bubba said.

    Hope this helps
    Just Google It. √

    (\ /)
    ( . .)
    c(")(") This is bunny. Copy and paste bunny into your signature to help him gain world domination.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. another do while question
    By kbpsu in forum C++ Programming
    Replies: 3
    Last Post: 03-23-2009, 12:14 PM
  2. inet_aton()... Noob needs help with sockets :|
    By Maz in forum C++ Programming
    Replies: 3
    Last Post: 11-22-2005, 03:33 PM
  3. question once again..
    By sunnycyboid in forum C Programming
    Replies: 1
    Last Post: 11-08-2002, 03:57 AM
  4. Algorithm question
    By PJYelton in forum C++ Programming
    Replies: 2
    Last Post: 10-28-2002, 09:52 AM
  5. Question type program for beginners
    By Kirdra in forum C++ Programming
    Replies: 7
    Last Post: 09-15-2002, 05:10 AM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21