Thread: Need simple code for large file handling

  1. #1
    Registered User
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    Need simple code for large file handling

    Hi all,

    I need a simple code for storing numeric data into a 2D matrix (consider dimensions are unknown) from a data-numeric format file.

    The file is uploaded here...

    http://archive.ics.uci.edu/ml/machin...n.data-numeric

    I have tried but somehow failed.

    Need your cooperation,

    thanks.

  2. #2
    Hurry Slowly vart's Avatar
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    somehow failed
    is very descriptive bug report
    Read this: http://cboard.cprogramming.com/annou...t.php?f=4&a=39

    post your last code
    describe your problem (what you expect, what you get, how it is different)
    ask for directions
    All problems in computer science can be solved by another level of indirection,
    except for the problem of too many layers of indirection.
    David J. Wheeler

  3. #3
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    I'm extremely sorry. I have forgot to post my code. Here it is...

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    struct matrix
    {
    	int nRow;
    	int nCol;
    	float **m;
    };
    
    typedef struct matrix *data;
    
    data getdata(char file_path_name[])
    {
    	FILE *db;
    	int ch;
    	int i, j, cols;
    	int rows = 0, entries = 0;
    
    	data ptrdata=(data)malloc(sizeof(data*)) ;
    	db = fopen(file_path_name, "r");
    
    	printf("\nCollecting information...\n");
    
    	while(1)
    		{
    			ch=fgetc(db);
    			if(ch==EOF)
    				{
    					//rows++;
    					//entries++;
    					break;
    					}
    			if(ch=='\n')
    				{
    					rows++;
    					entries++;
    					}
    			if(ch==' ')
    			entries++;
    			}
    
    	fclose(db);
    
    	cols = entries/rows;
    
    	printf("\nData contains %d rows and %d columns\n", rows, cols);
    
    	ptrdata->nRow = rows;
    	ptrdata->nCol = cols;
    
    	db = fopen("data.dat", "r");
    	ptrdata->m = (float **) malloc(rows * sizeof(float *));
    
    	for(i = 0; i < rows; i++)
    		ptrdata->m[i] = (float *) malloc(cols * sizeof(float));
    
    	for(i = 0; i < rows; i++)
    		for(j = 0; j < cols; j++)
    			fscanf(db, "%f", &(ptrdata->m[i][j]));
    
    	fclose(db);
    	return ptrdata;
    }
    
    int main()
    {
    	 char file_path_name[100];
    	 data pb;
    	 int i, j;
    
    	 printf("Provide name of the file (including path):\n");
    	 gets(file_path_name); //data.dat
    
    	 pb = getdata(file_path_name);
    
    	 printf("\nPrinting data matrix...\n\n");
    
    	 for(i = 0; i < pb->nRow; i++)
    	 //for(i = 0; i < 5; i++)
    	 {
    		for(j = 0; j < pb->nCol; j++)
    		//for(j = 0; j < 5; j++)
    		{
    			printf("%.2f ",*(*((pb->m)+i)+j));
    			}
    		putchar('\n');
    		}
    	 free(pb);
    	 return 0;
    	 }

  4. #4
    Frequently Quite Prolix dwks's Avatar
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    You still haven't said "what you expect, what you get, how it is different" -- which was good advice. As such, I'll have to guess.

    Some general guidelines:
    • Don't use gets(), it's dangerous. cpwiki.sf.net/Gets
    • You should free() your malloc()'d memory when you're done with it. (All dimensions.)


    As for your problem:
    Code:
    	for(i = 0; i < rows; i++)
    		for(j = 0; j < cols; j++)
    			fscanf(db, "&#37;f", &(ptrdata->m[i][j]));
    Try switching those for loops around . . . .
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
    "Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
    "The only real mistake is the one from which we learn nothing." -- John Powell


    Other boards: DaniWeb, TPS
    Unofficial Wiki FAQ: cpwiki.sf.net

    My website: http://dwks.theprogrammingsite.com/
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  5. #5
    Hurry Slowly vart's Avatar
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    Code:
    	db = fopen(file_path_name, "r");
    
    	db = fopen("data.dat", "r");
    you still have not fixed this
    as well as other notes made in the previos thread
    All problems in computer science can be solved by another level of indirection,
    except for the problem of too many layers of indirection.
    David J. Wheeler

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