how to read a file and split each readed line into variables or array

Question

Hi all and thanks a lot in advance, what am trying to acomplish here is that am reading a file with ansi C, this file contains text and for each line contains a string like this case:

andreuga|460325945878913024|Y sorry por los que no querían pero ITESO ahí te voy|1398585232|0|0

and what am already doing is that am reading that file.txt and split that string into this output:

res[0] = andreuga
res[1] = 460325945878913024
res[2] = Y sorry por los que no querÝan pero ITESO ahÝ te voy
res[3] = 1398585232
res[4] = 0
res[5] = 0
res[6] = (null)

so what i want to do is read the file and split the string while am reading each line and the save that value to a struct so later i can use that struct and insert into a database with another function i have. But my main issue is the spliting the string while reading each line from the file. This is the code:

#include <string.h>

int main(){
    char    str[]= "andreuga|460325945878913024|Y sorry por los que no querían pero ITESO ahí te voy|1398585232|0|0";
    char ** res  = NULL;
    char *  p    = strtok (str, "|");
    int n_spaces = 0, i;


    /* split string and append tokens to 'res' */

    while (p) {
      res = realloc (res, sizeof (char*) * ++n_spaces);

      if (res == NULL)
        exit (-1); /* memory allocation failed */

      res[n_spaces-1] = p;

      p = strtok (NULL, "|");
    }

    /* realloc one extra element for the last NULL */

    res = realloc (res, sizeof (char*) * (n_spaces+1));
    res[n_spaces] = 0;

    /* print the result */

    for (i = 0; i < (n_spaces+1); ++i)
      printf ("res[%d] = %s\n", i, res[i]);

    /* free the memory allocated */

    free (res);

    return 0;
}
///////////////////////OUTPUT:
res[0] = andreuga
res[1] = 460325945878913024
res[2] = Y sorry por los que no querÝan pero ITESO ahÝ te voy
res[3] = 1398585232
res[4] = 0
res[5] = 0
res[6] = (null)

Also to mention that in here i have an failed attempt to join the two codes.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//#include "libpq-fe.h"

#define LONG_MAX_LINEA  1024
#define NOM_ARCHIVO  "twitsDB.txt"


typedef struct tweet
{
 int  IDTweet;
 char IDCreator[20];
 char IDSentimentAnalysis[20];
 char HashTag[141];
 char Content[141];
 char CreationDate[30];    // time.h!!!
 char Retweet[20];
 char Favorites[20];
}Tweet;

int main(void)
{
   FILE *entrada;
   char linea[LONG_MAX_LINEA];

   char str[200];
   char ** res  = NULL;
   char *  p    = strtok (str, "|");
   int n_spaces = 0, i;
   int j = 0;

   printf("\n programa para leer una archivo");
   printf("\n-------------------------------");

   if ((entrada = fopen(NOM_ARCHIVO, "r")) == NULL){
      perror(NOM_ARCHIVO);
      return EXIT_FAILURE;
   }

   //Tweet tweet1;
   while (fgets(linea, LONG_MAX_LINEA, entrada) != NULL)
   {
      printf("%d %s", j,linea);


      //
        str[j] = linea;
        /* split string and append tokens to 'res' */

        while (p) {
          res = realloc (res, sizeof (char*) * ++n_spaces);

          if (res == NULL)
            exit (-1); /* memory allocation failed */

          res[n_spaces-1] = p;

          p = strtok (NULL, "|");
        }

        /* realloc one extra element for the last NULL */

        res = realloc (res, sizeof (char*) * (n_spaces+1));
        res[n_spaces] = 0;

        /* print the result */

        for (i = 0; i < (n_spaces+1); ++i)
          printf ("res[%d] = %s\n", i, res[i]);

        /* free the memory allocated */

        free (res);
      //

//      strcpy(tweet1.Content, "prueba tweet");
//      strcpy(tweet1.IDCreator, "1");
//      strcpy(tweet1.Favorites, "1");
//      strcpy(tweet1.Retweet, "1");
//      strcpy(tweet1.CreationDate, "2014-01-01");
//      strcpy(tweet1.HashTag, "1");
//      strcpy(tweet1.IDSentimentAnalysis, "1");



      //insertTweet(tweet1);
      // llenar la struct tweet

        j++;
        break;
   }


   fclose(entrada);
   puts("eso es todo el archivo");

   return EXIT_SUCCESS;
}

Hope i get to the point if not am constantly cheking for a better explanation. Cheers.

It seems time to start using a debugger to step through the code line by line inspecting all relevant variables to see what is really going on. — alk
– alk, Commented May 5, 2014 at 7:49

Leonardo Lourenço · Accepted Answer · 2014-05-06 22:10:57Z

2

That's strange... You declare str (line 77):

char str[200];

Then you apply strtok to trash values on str (since you didn't initialize it)... (line 79)

char *  p    = strtok (str, "|");

Then you use p without properly initiating the variable(line 101):

    while (p) {

Maybe the problem is somewhere along there?

==============================================

EDIT:

First, it seems you are trying to save linea in str, so, you'll need to change str's declaration to this:

char str[LONG_MAX_LINEA];

Because you need to make sure that the destination string will have enough space.

Then you can't try to assign doing str[j] = linea; this is WRONG! So that line should be changed to:

strcpy(str,linea);

Second, theres no point in doing strtok to trash value, so change p declaration to:

char *  p    = NULL;

Then, before the while, you write:

p = strtok (str, "|");

Does it work now?

edited May 6, 2014 at 22:10

answered May 5, 2014 at 5:24

Leonardo Lourenço

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4 Comments

GabouhSk8 Over a year ago

i don't know really am kind of stuck and some frustrated, in the link to the source code, only the split part it works, but when i try to combine the to source codes the one that split and the one that reads the file i just can't, maybe it's a wrong approach from the begining but in the main thing am trying to read a file in split each readed line and after read, split each line save it to struct and call a function to insert in the bd, if there is a better solution i would like to know

GabouhSk8 Over a year ago

i think i didn't mentioned but both codes work as they should independently, one splits the given string and the other one inserts into the database, just when i try to join the two codes i don't understand what am doing wrong and plus am not that experienced in C

Leonardo Lourenço Over a year ago

That's what I answered! You declare "char str[200];", since you didn't initilize it, it contains trash values. Then you apply strtok to trash and assign it to p (obviously wrong). And then you use this value on your while. You should apply strtok to what you read from file...

GabouhSk8 Over a year ago

yeah you're totally right, i was reviewing the code and there it was, i wasn't splitting correctly. I was really confused but now it's solved

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