3-d array assign string values

This is a discussion on 3-d array assign string values within the C++ Programming forums, part of the General Programming Boards category; OK, xsquared and the brain got me out of my last learning crush on arrays and I'm hoping someone can ...

  1. #1
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    3-d array assign string values

    OK, xsquared and the brain got me out of my last learning crush on arrays and I'm hoping someone can help again....

    I'm creating a 3d array of strings and then trying to input an unknown number of records into the specific areas from a file using strcpy to assign variables to the array values. LOST? Me too...
    heres the array
    Code:
    char waves [21] [300] [5] [31];
    21 represents the number of tables to be created
    300 represents the number of rows for each table
    5 represents the number of columns for each table
    31 represents the number of characters each string can be within the 5 columns.

    heres the code on how it is used, here I am just trying to assign the input from a file recId to the rows in all 21 tables in sequence:
    Code:
    ifstream fin1;
    		fin1.open("C:\\palletperf.txt");
    		if (fin1.fail())
    		{
    			cout <<"failed to open palletperf.txt";
    		}
    		
    		ifstream fin2;
    		fin2.open("C:\\partnerlist.txt");
    		if (fin2.fail())
    		{
    			cout <<"failed to open partnerlist.txt";
    		}
    
    		//declare 3-d array waves
    		char waves [21] [300] [5] [31];
    
    		//insert partnerlist records and poplulate all waves tables
    		do
    		{
    			do
    			{
    				char partRow [11];
    				fin2>>recName;
    				fin2>>recId;
    				strcpy(waves[waveTableCount][partRow], recId );
    			}while (!fin2.eof());
    			fin2.close();
    			waveTableCount++;
    
    		}while (waveTableCount <=21);
    since arrays are new to me... I'm biting off alot. I've drawn the array out on paper to keep a visual, thats why I explain it from table point of few, can ya tell I'm reading a book????LOL!

    Thanks for any help-

  2. #2
    & the hat of GPL slaying Thantos's Avatar
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    1) You have a 4 dimensional array not a 3 dimensional array
    2) I think its time you shifted your way of thinking of multidimensional arrays. The row col thing works fine for 2 and kinda works for 3 dimensions but with 4 or above it breaks down. I posted a nice (IMO) tree structure that you might find help. n dimensional arrays

  3. #3
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    cool, thanks Thantos, I'll check it out.

  4. #4
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    Hey Thantos,
    your posting does help to view that complex of array, but for the info I want to assign is there a way to use a 3d array?

    the only reason I use the 4th set is because its an array of strings and I thought I needed to establish the length of the string. Is that not necessary? I got if from a book I used while studying arrays.

  5. #5
    & the hat of GPL slaying Thantos's Avatar
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    Well strings are nothing more then a fancy array of characters. So if you have an array of strings you really have a 2 dimensional array.

    The question(s) I have for you is why do you want to setup your table like that?
    Would using std::string be easier?

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    I need to pass through a large file, say about 50, 000 lines with 5 different elements per line each line could relate to one of 20 different persons. I'm trying to make one pass store the data in ram so this is a fast process and then make calculations on the accumulated data from each line for each person.

    doing a search and handle on so many strings in such a large file was cpu intensive and a huge time hog! So I started researching the use of arrays.

    I appreciate your help and taking time look at this, it is a big help. I was actually thinking of using 20 different 2 d arrays and just filling them accordingly and then using their data. But I still have a problem assign the values of the strings from the file input into the proper areas of the array. 1d array no prob 2 or > not good.

  7. #7
    & the hat of GPL slaying Thantos's Avatar
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    How about using structures and having an array of structures. Also you might look into a way to process the information as you read it instead of storing it and then reading it.

  8. #8
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    I will have to research structs, but that sounds worth it. I will start in my books and follow your idea and see what I can do. Probably see a post soon on structs, LOL! Thanks for the idea, I will start looking into it.

  9. #9
    and the hat of wrongness Salem's Avatar
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    > the only reason I use the 4th set is because its an array of strings and I thought I needed to establish the length of the string
    You are correct.
    You can view it as a 4D array of chars, or
    You can view it as a 3D array of strings (upto 30 chars in length, +1 for the \0)

    > strcpy(waves[waveTableCount][partRow], recId );
    You need a 3rd index
    strcpy(waves[Table][Row][Column], recId );
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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