Problems printing a linked list.

[Ed_Severson]

I'm trying to construct a linked list from a *.dat file, and then display the nodes to verify the read-in. But, when I run the program, I only get the last node displayed to the screen.

Can someone tell me why this is?

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

struct savingsnode
{
char comment[32] ;
char deb_cred[8] ;
double amt ;
char date[12] ;
double bal ;
struct savingsnode *nextptr ;
} ;

typedef struct savingsnode Savings ;
typedef Savings *saveptr ;

void save_open( saveptr * ) ;
void save_display( saveptr * ) ;

int main()
{

saveptr startptr ;

startptr = malloc( sizeof( Savings ) ) ;

printf( "\n\nWelcome to Finance Assitant!\n\n" ) ;

save_open( &startptr ) ;

save_display( &startptr) ;
}

/*****************************************
Function: save_open
Purpose: Opens the savings.dat file and
creates the savings linked list.
*****************************************/
void save_open( saveptr *sptr)
{

FILE *ptrReadDat ;
char NewLine[256] = {'\0'} ;
char *tokenptr ;
saveptr curptr, newptr ;

ptrReadDat = fopen( "savings.dat", "r" ) ;
curptr = *sptr ;
newptr = NULL ;
curptr->nextptr = newptr ;

if ( ptrReadDat == NULL )
printf( "\nFile could not be opened.\n" ) ;

else
{
while( fgets( NewLine, 256, ptrReadDat ) ) ;
{
tokenptr = strtok( NewLine, "\t" ) ;
strcpy( curptr->comment, tokenptr ) ;
tokenptr = strtok( NULL, "\t" ) ;
strcpy( curptr->deb_cred, tokenptr ) ;
tokenptr = strtok( NULL, "\t" ) ;
curptr->amt = atof( tokenptr ) ;
tokenptr = strtok( NULL, "\t" ) ;
strcpy( curptr->date, tokenptr ) ;
tokenptr = strtok( NULL, "\n" ) ;
curptr->bal = atof( tokenptr ) ;
newptr = malloc( sizeof( Savings ) ) ;
curptr->nextptr = newptr ;
curptr = newptr ;
newptr = NULL ;
}

fclose( ptrReadDat ) ;
}

}

/**********************************************
Function: save_display
Purpose: Displays the savings account summary.
**********************************************/
void save_display( saveptr *sptr )
{

saveptr curptr ;
curptr = *sptr ;

if ( curptr == NULL )
printf( "There is no information to display." ) ;

else
{
while ( curptr != NULL )
{
printf( "%s\t%s\t%.2f\t%s\t%.2f\n", curptr->comment, curptr->deb_cred,
curptr->amt, curptr->date, curptr->bal ) ;
curptr = curptr->nextptr ;
}
}

}

[ygfperson]

*gasp*
what, no code tags? to hell i cast you!

[Ed_Severson]

Well, that was helpful.

[sean345]

This happened to me once. What happened was I was using malloc and sizeof. What I was doing was taking the size of a pointer and not an actual structure. I did not read all your code, but this might be your problem.

- Sean

[Sebastiani]

void save_open( saveptr *sptr) 
{ 

FILE *ptrReadDat ; 
char NewLine[256] = {'\0'} ; 
char *tokenptr ; 
saveptr newptr, curptr = *sptr; 

ptrReadDat = fopen( "savings.dat", "r" ) ;

if ( ptrReadDat == NULL )
{ 
 printf( "\nFile could not be opened.\n" ) ; 
 return;
} 



while( fgets( NewLine, 256, ptrReadDat ) ) 
 { 
  
   newptr = malloc( sizeof( Savings ) ) ; //...allocate new memory...

  if(newptr == NULL)
  { 
    printf( "\nCould not allocate resources.\n" ) ; 
    return;
  }

   newptr->nextptr = NULL; 
   curptr->nextptr = newptr ; //...point to new memory...
   curptr = curptr->nextptr;  //...advance to new memory for next iteration...
   tokenptr = strtok( NewLine, "\t" ) ; 
   strcpy( newptr->comment, tokenptr ) ; 
   tokenptr = strtok( NULL, "\t" ) ; 
   strcpy( newptr->deb_cred, tokenptr ) ; 
   tokenptr = strtok( NULL, "\t" ) ; 
   newptr->amt = atof( tokenptr ) ; 
   tokenptr = strtok( NULL, "\t" ) ; 
   strcpy( newptr->date, tokenptr ) ; 
   tokenptr = strtok( NULL, "\n" ) ; 
   newptr->bal = atof( tokenptr ) ; 
 } 

fclose( ptrReadDat ) ; 
}