What's wrong with my read function? read from a txt file to an array of object

This is a discussion on What's wrong with my read function? read from a txt file to an array of object within the C++ Programming forums, part of the General Programming Boards category; i need to read data from my txt file and iv got another function to print, but something must be ...

  1. #1
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    Exclamation What's wrong with my read function? read from a txt file to an array of object

    i need to read data from my txt file and iv got another function to print, but something must be wrong with my read function b/c my values turn out to be random negatives

    read function
    Code:
    int read(Item Itemlist[], string filename)
    {
        int i=0;
        
        ifstream infile( filename.c_str() );
        while( !infile.eof())
            {
                cout << "read file" <<endl;
                infile>>Itemlist[i].ID;
                infile>>Itemlist[i].sold;
                infile>>Itemlist[i].rem;
                i++;
        }
        return i;
    }
    and the class
    Code:
    class Item
    {
    public:
        string ID;
        int rem;
        int sold;
    };
    a piece of main
    Code:
    Item myArray[100];
        int numOfRecs=read( myArray, "inventory (1).txt");
    I'm almost sure it the problem isn't my print function.

  2. #2
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    My txt file im trying to read from is formatted like this
    Code:
    619847GBE 641 998
    418712IMB 107 867
    227451GEM 789 181
    981836KEA 747 171
    986516IGU 303 71

  3. #3
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    I do know that my program gets into my file because the "read file" does come up on my output but the values i get along with it are not the same values that i should be getting.
    What i needed is "619847GBE" stored in my Item array[i].ID, "641" as my arrays sold int and "998" as my arrays rem int and so on. Could it be the actual reading of it that i need to corrrect?
    Code:
    infile>>Itemlist[i].ID;
    infile>>Itemlist[i].sold;
    infile>>Itemlist[i].rem;
    i++;
    

  4. #4
    and the hat of int overfl Salem's Avatar
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    You mean like this?
    Code:
    $ ./a.out 
    read file
    read file
    read file
    read file
    read file
    read file
    619847GBE 998 641 
    418712IMB 867 107 
    227451GEM 181 789 
    981836KEA 171 747 
    986516IGU 71 303 
     -964689920 -22220 
    $
    The problem is this
    SourceForge.net: Feof - cpwiki

    Your loop should be
    Code:
    while ( infile>>Itemlist[i].ID ) {
                infile>>Itemlist[i].sold;
                infile>>Itemlist[i].rem;
                i++;
    }
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  5. #5
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    Yes exactly like that! I'm going over the link and changed my loop, but having a little trouble adjusting. Output still the same Changing my code as you read

  6. #6
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    Its not working out
    Code:
     -858993460 -858993460
     -858993460 -858993460
     -858993460 -858993460
    Press any key to continue . . .
    thats my output i took off the read

  7. #7
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    Solution
    This worked just fine. The mistake was coming from main. Minor error was ruining my read before i even called it. don't i feel embarrassed. but glad it really wasn't my read function
    Code:
    int read(Item Itemlist[], string filename)
    {
    	int i=0;
    	
    	ifstream infile( filename.c_str() );
    	while (!infile.eof() ) 
    	{
    		
    		{
    				infile>>Itemlist[i].ID;
    				infile>>Itemlist[i].sold;
    				infile>>Itemlist[i].rem;
    				i++;
    		}
    		
    	}
    		return i;
    }

  8. #8
    and the hat of int overfl Salem's Avatar
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    Your read function is still broken, if it's still got this in it.
    while (!infile.eof() )

    Study post #4 carefully.
    6 lines of "read file" printed for a 5-line input file, and a garbage last line of data is printed.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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