Read/parse file in C

[abargo]

Hi...

I'm trying to figure out how to read in a file for a database program I'm making

This is what I have:

// ********************************************************************************
// FUNCTION: LOAD FILE
//
// Loads a text file into the database. Does not take any input, only uses the
// string that is given to it.
// *****************************************************************************

int loadFile ( char *fileName )
{
char choice, trash[5];
char readInBuffer[sizeof personType], *strTemp;
char *pToken; // points to where comma is found
bool temp = false;

FILE *pFile; // file pointer

// gets input (overwrite or append)
do
{
if (strlen(message)) printf("%s\n", message);
strcpy(message, ""
printf("Would you like to (a)ppend or (o)verwrite your currently loaded database? "
scanf("%c", &choice);
gets(trash);
if (choice != 'o' && choice != 'a')
strcpy(message, "Please enter a valid choice."
} while (strlen(message));

// clear database if they chose to
if (choice == 'o')
{
purgeDatabase();
temp = true;
}

// open the file
pFile = fopen(fileName, "r"

if (pFile == NULL) // checks to see if it actually opened
return 1;

// keep adding records until the end of the file
while (!feof(pFile))
{
// add one to record count
recCount++;

// previous record is now the last record, because we create a new one
(temp) ?
pPrevious = NULL : pPrevious = pLastRec;

// allocate a persontype struct for the current one
pLastRec = (struct personType *) malloc(sizeof (struct personType) );
if (pLastRec == NULL)
{
printf("Memory allocation failed, please free up more memory.\n"
system("pause"
return 1;
}
// no next, so null pointer
pLastRec->next = NULL;


// the previous->next one is this new record
if (pPrevious != NULL)
pPrevious->next = pLastRec;

// if pFirst is the previous record, then point the first record to this new one (only happens once)
if (temp)
{
pFirst->next = pLastRec;
temp = false;
}
fgets(readInBuffer, sizeof readInBuffer, pFile);

// use strtok to find the comma and parse the before it

pToken = strtok( readInBuffer, "," );

sscanf( strTemp, "%s", &pLastRec->lastName );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%s", &pLastRec->firstName );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%d", &pLastRec->age );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%c", &pLastRec->sex );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%c", &pLastRec->hairColor );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%d", &pLastRec->height );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%d", &pLastRec->weight );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%s", pLastRec->car, pToken );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%c", &pLastRec->carColor );
pToken = strtok( NULL, "," );
strTemp = pToken;
sscanf( strTemp, "%d", &pLastRec->income );
pLastRec->number = recCount;

}

fclose(pFile);
pCurrent = pLastRec;
return 0;
}
the file is formatted like this:
argo,adam,19,m,y,74,220,explorer,g,100

it reads into a structure:
struct personType
{
char lastName[MAXSTRLEN]; // person's last name
char firstName[MAXSTRLEN]; // person's first name
int age; // person's age
char sex; // person's sex (m f)
char hairColor; // person's hair color (k y r b w g o)
int height; // person's height
int weight; // person's weight
char car[20]; // person's car
char carColor; // person's car color (k y r b w g t a o)
int income; // person's annual income, dollar
int number; // record number
personType *next; // pointer to next record
} *pFirst, *pCurrent, *pPrevious, *pLastRec;

it crashes every time... please help!

 

[gonzilla]

Hi,

You need to point strTemp somewere before you can use it in this line...

sscanf( strTemp, "%s", &pLastRec->lastName );

One way would be to do this...

pToken = strtok( readInBuffer, "," );
strTemp=pToken;

...after your first call to strtok()

I tested it and it worked fine. I'm sure there are better ways.

BTW - You don't need to have (..., &pLastRec->lastName );

You should be fine with pLastRec->lastName (no '&') since pLastRec points where you need it anyway. Both work, just looks strange to me. This is the same for any of the array names, not for the other types.

Hope that helped.

-Tyler