Segmentation Error

For some reason I keep on getting a segmentation error when trying to run the code.

Does anyone know how I can fix it?:

Code:

#include <stdio.h>
#include <string.h>
#define MAXLEN     120 


void checkin()
{
   typedef struct {
        char reservationId[7];
        char customerId[7];
        char roomId[5];
        int numGuests;
        char startDate[10];
        char endDate[10];
        char status[10];	


               }bookingdata;

   bookingdata record[100];

   FILE * filehandle;
   char line[MAXLEN];

   char *item = NULL;
   int reccount = 0;
   int k;

   /* Here comes the actions! */
   /* open file */

   filehandle = fopen("booking.txt","r");

   /* Read file line by line */

   while (fgets(line,MAXLEN,filehandle)) 
      {
          printf("%s",line);

          item = strtok(line," ");
          strcpy(record[reccount].reservationId,item);

          item = strtok(NULL," ");
          strcpy(record[reccount].customerId,   item);

          item = strtok(NULL," ");
          strcpy(record[reccount].roomId,   item);

          item = strtok(line," ");
          record[reccount].numGuests = atoi(item);

          item = strtok(NULL," ");
          strcpy(record[reccount].startDate,   item);

          item = strtok(NULL,"\n");
          strcpy(record[reccount].endDate,   item);


          //printf("%s\n",record[reccount].day);
          reccount++;



       }

   /* Close file */

   fclose(filehandle);


/* Loop through and report on data */

printf("Weather Record\n");
for (k=0; k<reccount; k++) {
           printf("It is %s\n",record[k].reservationId);

}
}

main()
{
   checkin();
}

For starts move the struct typedef out of your checkin function...
Place it at global scope right below your #includes...

Why don't you just use sscanf instead of strtok? You don't say where you get a segfault, or where you see any output. You should check to see that your file actually opens before you start trying to read from it. Do you see any lines output from your loop? How many? How many are in your file?


Quzah.

Originally Posted by quzah

You don't say where you get a segfault, or where you see any output. You should check to see that your file actually opens before you start trying to read from it. Do you see any lines output from your loop? How many? How many are in your file?


Quzah.

The segmentation error occurs here:

Code:

item = strtok(line," ");
          strcpy(record[reccount].reservationId,item);

and the only line that outputs in the loop is the first printf.

Originally Posted by CommonTater

For starts move the struct typedef out of your checkin function...
Place it at global scope right below your #includes...

Ha! Sorry about that. Although I'm still getting the segmentation error.

How long is your reservationID? If it's 7 characters you don't have enough room in your struct for it...

A string of 7 characters requires 8 bytes of space... Every string requires at least 1 extra byte to hold the trailing null.

Code:

while( fgets( line, MAXLEN, filehandle ) != NULL )
{
    printf( "%s\n", line );
    if( sscanf( line, "%6s %6s %4s %d %9s %9s %9s",
        record[reccount].reservationId, record[reccount].customerId,
        record[reccount].roomId, &record[reccount].numGuests,
        record[reccount].startDate, record[reccount].endDate,
        record[reccount].status ) != 7 )
    {
        ...error...
    }
    else
    {
        ...yay...
    }
}

Try that.


Quzah.

@CommonTater

THe length of the reservationId is 6 characters hence why I put 7.

Read up on strtok. If there's no space character in line, item will be null, which is probably the cause of your seg fault. Just because the first printf in the loop is the last output you see doesn't mean that the next line causes the seg fault. What is the exact contents of line that are printed just before the crash? If you have only 2 spaces in there, the third or fourth strtok will fail. Can you run this in a debugger and step through to see where it actually seg faults? If not, print out each item immediately after you read it it.

Originally Posted by anduril462

Read up on strtok. If there's no space character in line, item will be null, which is probably the cause of your seg fault. Just because the first printf in the loop is the last output you see doesn't mean that the next line causes the seg fault. What is the exact contents of line that are printed just before the crash? If you have only 2 spaces in there, the third or fourth strtok will fail. Can you run this in a debugger and step through to see where it actually seg faults? If not, print out each item immediately after you read it it.

This is the line that gets printed before the crash anduril:

RES001;CUS001;R101;1;05/06/2011;08/06/2011;reserved
Segmentation fault

Originally Posted by david.jones

This is the line that gets printed before the crash anduril:

RES001;CUS001;R101;1;05/06/2011;08/06/2011;reserved
Segmentation fault

Why are you using " " when you should be using ";" for strtok?


Quzah.

Originally Posted by quzah

Why are you using " " when you should be using ";" for strtok?


Quzah.

sorry about that. I was playing around with code while waiting for a response so I copied the bit I modified.
However i still receive a segmentation error.

As anduril462 says, each strtok() result needs to be checked for NULL before you use it.

Code:

item = strtok(line," ");
if ( item != NULL ) {
    strcpy(record[reccount].reservationId,item);
} else {
    // do something else, say error message
}

Originally Posted by david.jones

@CommonTater

THe length of the reservationId is 6 characters hence why I put 7.

Excellent. You'd be surprised now many people don't think about that.

nevermind