Thread: Linked List problem

cool fixed up the code, however theres something REALLY REALLY REALLY WEIRD, possibly my compiler, for some reason if i dont have the part with the enter number at the start i get faults happening when the file is read in and it gets to the balance

Code:

#include <stdio.h> 

typedef struct customer 
{ 
  char fname[20]; 
  char lname[20]; 
  char initial;
  long socialnum;
  double balance;
  struct customer *next;
}CUSTOMER; 

int main() 
{ 
  FILE *infile; 
  CUSTOMER *bankrecords;
  CUSTOMER *tempptr;

double balance;
//FOR SOME WEIRD ARSE REASON WITHOUT THIS IT CRASHES, ANY IDEAS ANYONE?
printf("press a number else it doesnt work, no idea why");
scanf("%lf",&balance);

  bankrecords=NULL;

  infile=fopen("data.dat","r"); 
  if(infile == NULL)
  { 
    printf("Data file could not be opened.\n"); 
  }
  else
  {

// READ IN ALL THE FILE INTO THE LIST
    while(!feof(infile))
    {
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
      }
      else
      {
        tempptr = bankrecords;
        while(tempptr->next!=NULL)
          tempptr=tempptr->next;
        tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr=tempptr->next;
      }
      fscanf(infile,"%s %s %c %D %lf",tempptr->fname,tempptr->lname,&(tempptr->initial),&(tempptr->socialnum),&(tempptr->balance));
      tempptr->next=NULL;
    }
    fclose(infile);


// PRINT ALL THE LIST
    tempptr = bankrecords;
    printf("NUM ADDRESS LAST\tFIRST MI\tSSN BALANCE NEXT\n"); 
    printf("-----------------------------------------------------\n\n"); 
    while(tempptr!=NULL)
    {
      printf("%s %c %s %ld %.2lf\n",tempptr->fname,tempptr->initial,tempptr->lname,tempptr->socialnum,tempptr->balance);
      tempptr=tempptr->next;
    }
  }
  return 1;
}

oviously you'll need to format the output, ie to do the account number properly do %15d and it will right align (i think) everything giving 15 spaces.

also if you need to free up the memory yourself rather than letting the os do it then I suggest making it a double linked list, heaps easier to free large amounts of memory and quicker.
Hope this helps

<quote>code
#include <stdio.h>

typedef struct customer
{
char fname[20];
char lname[20];
char initial;
long socialnum;
double balance;
struct customer *next;
}CUSTOMER;

int main()
{
FILE *infile;
CUSTOMER *bankrecords;
CUSTOMER *tempptr;
clrscr();

/*double balance;*/
/*FOR SOME WEIRD ARSE REASON WITHOUT THIS IT CRASHES, ANY IDEAS ANYONE?*/
/*printf("press a number else it doesnt work, no idea why");
scanf("%lf",&balance);*/

bankrecords=NULL;

infile=fopen("data.dat","r");
if(infile == NULL)
{
printf("Data file could not be opened.\n");
}
else
{

/* READ IN ALL THE FILE INTO THE LIST*/
while(!feof(infile))
{
if(bankrecords==NULL)
{
bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
tempptr = bankrecords;
}
else
{
tempptr = bankrecords;
while(tempptr->next!=NULL)
tempptr=tempptr->next;
tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
tempptr=tempptr->next;
}
fscanf(infile,"%s %s %c %D %lf",tempptr->fname,tempptr->lname,&(tempptr->initial),&(tempptr->socialnum),&(tempptr->balance));
tempptr->next=NULL;
}
fclose(infile);


/* PRINT ALL THE LIST */
tempptr = bankrecords;
printf("LAST\tMI\tFIRST\t SSN \t\tBALANCE \t\n");
printf("-----------------------------------------------------\n\n");
while(tempptr!=NULL)
{
printf("%s\t %c\t %s\t %ld\t %.2lf\n",tempptr->fname,tempptr->initial,tempptr->lname,tempptr->socialnum,tempptr->balance);
tempptr=tempptr->next;
}
}
getch();
return 1;
}

</quote>

the code is working without reading that double value, Bull. I think you better use a good ol C compiler, rather than a state-of-the art new win32 CPP compiler. You can find one such nice compiler at http://community.borland.com.

Borland is giving away its TurboC 2.1 compiler for free. All u need to do is register there and download it from their Museum.

Note: i made some changes in printf's which will be working fine on my system.

--cheers.

I need the data to print right because the data file im reading from is not formatted so it might have something like:

Jones Mike K 857102563 214.36
Matty Joe L 142036987 1487.24

So when i output the data it does not line up correctly.

Code:

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



typedef struct customer 
{ 
	char fname[20]; 
	char lname[20]; 
	char initial;
	int socialnum;
	double balance;
	struct customer *next;
}CUSTOMER;

int main() 
{ 
	FILE *infile; 
	CUSTOMER *bankrecords;
	CUSTOMER *tempptr;
	int track=1;

	

	


	bankrecords=NULL;

	infile=fopen("data.dat","r"); 
	if(infile == NULL)
	{ 
		printf("Data file could not be opened.\n"); 
	}
	else
	{

	

	 
    while(!feof(infile))
    {
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
      }
      else
      {
        tempptr = bankrecords;
        while(tempptr->next!=NULL)
          tempptr=tempptr->next;
        tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr=tempptr->next;
      }
      fscanf(infile,"%s %s %c %d %lf",&tempptr->lname,&tempptr->fname,&tempptr->initial,&tempptr->socialnum,&tempptr->balance);
      tempptr->next=NULL;
    }
    fclose(infile);


// PRINT ALL THE LIST
    tempptr = bankrecords;
    printf("NUM\tADDRESS    LAST\tFIRST  MI   SSN        BALANCE    NEXT\n"); 
    printf("-----------------------------------------------------------\n\n"); 
    while(tempptr!=NULL)
    {
      printf("%d   %8X\t  %s \t%s   %c   %d   %.2lf  %8X\n",track,tempptr,tempptr->lname,tempptr->fname,tempptr->initial,tempptr->socialnum,tempptr->balance,tempptr->next);
	  track++;
      tempptr=tempptr->next;
    }
  }
  return 0;
}

ok as of right now if my input file has the following:

Johnson Mike J 253657410 19473.00
Mack Johnny T 230459630 21045.00
Jackson Lewis J 069741052 25.69

And i run my program my output does this:

Code:

NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
----------------------------------------------------------------

1      430090   Johnson         Mike      J   253657410   19473.00    431E60
2      431E60   Mack            Johnny    T   230459630   21045.00    431DF0
3      431DF0   Jackson         Lewis     J    69741052   25.69       0
Press any key to continue

how can i get it to print like this:

NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
----------------------------------------------------------------

1      430090   Johnson         Mike      J   253657410   19473.00    NULL


NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
----------------------------------------------------------------
1      430090   Johnson         Mike      J   253657410   19473.00    431E60
2      431E60   Mack            Johnny    T   230459630   21045.00    NULL

NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
----------------------------------------------------------------

1     431DF0   Jackson         Lewis     J    69741052   25.69         431E62

2     430090   Johnson         Mike      J   253657410   19473.00    431E60

3      431E60   Mack            Johnny    T   230459630   21045.00    NULL

It has to sort the names by alphabetical order by last names and if last names are the same go by first names.

oh yeah here is my code:

Code:

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



typedef struct customer 
{ 
	char fname[20]; 
	char lname[20]; 
	char initial;
	int  socialnum;
	double balance;
	struct customer *next;
}CUSTOMER;

int main() 
{ 
	FILE *infile; 
	CUSTOMER *bankrecords;
	CUSTOMER *tempptr;
	int track=1;

	

	


	bankrecords=NULL;

	infile=fopen("data.dat","r"); 
	if(infile == NULL)
	{ 
		printf("Data file could not be opened.\n"); 
	}

    while(!feof(infile))
    {
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
      }
      else
      {
        tempptr = bankrecords;
        while(tempptr->next!=NULL)
          tempptr=tempptr->next;
        tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr=tempptr->next;
      }
      fscanf(infile,"%s %s %c %d %lf",&tempptr->lname,&tempptr->fname,&tempptr->initial,&tempptr->socialnum,&tempptr->balance);
      tempptr->next=NULL;
    }
    fclose(infile);


// PRINT ALL THE LIST
    tempptr = bankrecords;
    printf("NUM\tADDRESS    LAST\t     \tFIRST   MI    SSN        BALANCE    NEXT\n"); 
    printf("----------------------------------------------------------------\n\n"); 
    while(tempptr!=NULL)
    {
      printf("%d    %8X\t%-12s \t%-9s %1c   %9d   %.2lf  %8X\n",track,tempptr,tempptr->lname,tempptr->fname,tempptr->initial,tempptr->socialnum,tempptr->balance,tempptr->next);
	  track++;
      tempptr=tempptr->next;
    }
  
	return 0;
}

ok but what about getting it to print out the way i showed in my last 2 posts?

im not understanding what you typed. I mean i sort of understand but not completely

ok the easiest way to do that is probably to sort it as its being inserted into the list and then just print them out as normal, below is the code i posted which your using now but modified which sorts the list on insertion:

Code:

#include <stdio.h> 

typedef struct customer 
{ 
  char fname[20]; 
  char lname[20]; 
  char initial;
  long socialnum;
  double balance;
  struct customer *next;
}CUSTOMER; 

int main() 
{ 
  FILE *infile; 
  CUSTOMER *bankrecords;
  CUSTOMER *tempptr;
  CUSTOMER *tempptr2;
  CUSTOMER temprecord;

  bankrecords=NULL;

  infile=fopen("data.dat","r"); 
  if(infile == NULL)
  { 
    printf("Data file could not be opened.\n"); 
  }
  else
  {

// READ IN ALL THE FILE INTO THE LIST
    while(!feof(infile))
    {
      fscanf(infile,"%s %s %c %D %lf",temprecord.fname,temprecord.lname,&(temprecord.initial),&(temprecord.socialnum),&(temprecord.balance));
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
        tempptr->next=NULL;
      }
      else				// RECORDS ALREADY EXIST
      {
        tempptr = bankrecords;
        while((tempptr->next!=NULL) && (strcmp(tempptr->fname,temprecord.fname)<0))
          tempptr=tempptr->next;

        if(bankrecords==tempptr)	// RECORD BELONGS AT START OF LIST
        {
          tempptr2=tempptr;
          bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr = bankrecords;
        }
        else				// RECORD IS SOMEWHERE IN MIDDLE OR END
        {
          tempptr2=tempptr->next;
          tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr=tempptr->next;
        }
        tempptr->next=tempptr2;
      }

      //COPY ALL DATA FROM TEMP RECORD TO NEW ONE
      strcpy(tempptr->fname,temprecord.fname);
      strcpy(tempptr->lname,temprecord.lname);
      tempptr->initial = temprecord.initial;
      tempptr->socialnum = temprecord.socialnum;
      tempptr->balance = temprecord.balance;
    }
    fclose(infile);


// PRINT ALL THE LIST
    tempptr = bankrecords;
    printf("NUM ADDRESS LAST\tFIRST MI\tSSN BALANCE NEXT\n"); 
    printf("-----------------------------------------------------\n\n"); 

    while(tempptr!=NULL)
    {
      printf("%s %c %s %ld %.2lf\n",tempptr->fname,tempptr->initial,tempptr->lname,tempptr->socialnum,tempptr->balance);
      tempptr=tempptr->next;
    }
  }
  return 1;
}

you can either cut bits out or create 2 new variables as:

Code:

  CUSTOMER *tempptr2;
  CUSTOMER temprecord;

and then change the code within the while(!feof(infile)) to

Code:

    while(!feof(infile))
    {
      fscanf(infile,"%s %s %c %D %lf",temprecord.fname,temprecord.lname,&(temprecord.initial),&(temprecord.socialnum),&(temprecord.balance));
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
        tempptr->next=NULL;
      }
      else				// RECORDS ALREADY EXIST
      {
        tempptr = bankrecords;
        while((tempptr->next!=NULL) && (strcmp(tempptr->fname,temprecord.fname)<0))
          tempptr=tempptr->next;

        if(bankrecords==tempptr)	// RECORD BELONGS AT START OF LIST
        {
          tempptr2=tempptr;
          bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr = bankrecords;
        }
        else				// RECORD IS SOMEWHERE IN MIDDLE OR END
        {
          tempptr2=tempptr->next;
          tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr=tempptr->next;
        }
        tempptr->next=tempptr2;
      }

      //COPY ALL DATA FROM TEMP RECORD TO NEW ONE
      strcpy(tempptr->fname,temprecord.fname);
      strcpy(tempptr->lname,temprecord.lname);
      tempptr->initial = temprecord.initial;
      tempptr->socialnum = temprecord.socialnum;
      tempptr->balance = temprecord.balance;
    }

hope this helps

ok I am continuing to have issues with printing out each record one at a time. When ever i modify my code i can never get it go print out one at a time instead it prints out all of them.

The data i am using for input looks like this:

Johnson Mike J 253657410 19473.00
Mack Johnny T 230459630 21045.00
Jackson Lewis J 169741052 2579.69
Zunny Jack L 065523069 25144.36
Ashberry Jim P 741803205 26390.54

i want it to first print out the first persons info like this:

Code:

NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
-------------------------------------------------------------------------------

1      431DB0   Ashberry        Jim       P   741803205   26390.54    NULL

Then print out:

Code:

NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
-------------------------------------------------------------------------------

1      431DB0   Ashberry        Jim       P   741803205   26390.54    431E90

2      431E90   Jackson         Lewis     J   169741052   2579.69    NULL

Then print:

Code:

NUM     ADDRESS    LAST         FIRST   MI    SSN        BALANCE    NEXT
-------------------------------------------------------------------------------

1      431DB0   Ashberry        Jim       P   741803205   26390.54    431E90

2      431E90   Jackson         Lewis     J   169741052   2579.69    431F00

3      431F00   Mack            Johnny    T   230459630   21045.00    NULL

And so on.....

what am i doing wrong?

you basically need a counter and loop through until you are at the end, so through the first pass it will print 1, then 2, and so on, also I screwed a little of the code b4, below is all the code, works perfect on my pc, and sorts them properly now:

Code:

#include <stdio.h> 

typedef struct customer 
{ 
  char fname[20]; 
  char lname[20]; 
  char initial;
  long socialnum;
  double balance;
  struct customer *next;
}CUSTOMER; 

int main() 
{ 
  FILE *infile; 
  CUSTOMER *bankrecords;
  CUSTOMER *tempptr;
  CUSTOMER *tempptr2;
  CUSTOMER temprecord;
  int counter1,counter2;

  bankrecords=NULL;

  infile=fopen("data.dat","r"); 
  if(infile == NULL)
  { 
    printf("Data file could not be opened.\n"); 
  }
  else
  {

// READ IN ALL THE FILE INTO THE LIST
    while(!feof(infile))
    {
      fscanf(infile,"%s %s %c %D %lf",temprecord.fname,temprecord.lname,&(temprecord.initial),&(temprecord.socialnum),&(temprecord.balance));
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
        tempptr->next=NULL;
      }
      else				// RECORDS ALREADY EXIST
      {
        tempptr = bankrecords;
        while((tempptr->next!=NULL) && (strcmp(tempptr->fname,temprecord.fname)<0))
          tempptr=tempptr->next;

        if((bankrecords==tempptr) && (strcmp(tempptr->fname,temprecord.fname)>0))	// RECORD BELONGS AT START OF LIST
        {
          tempptr2=tempptr;
          bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr = bankrecords;
        }
        else				// RECORD IS SOMEWHERE IN MIDDLE OR END
        {
          tempptr2=tempptr->next;
          tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr=tempptr->next;
        }
        tempptr->next=tempptr2;
      }

      //COPY ALL DATA FROM TEMP RECORD TO NEW ONE
      strcpy(tempptr->fname,temprecord.fname);
      strcpy(tempptr->lname,temprecord.lname);
      tempptr->initial = temprecord.initial;
      tempptr->socialnum = temprecord.socialnum;
      tempptr->balance = temprecord.balance;
    }
    fclose(infile);


// PRINT ALL THE LIST
    tempptr = bankrecords;

    for(counter1=0;tempptr!=NULL;counter1++)
    {
      tempptr = bankrecords;
      printf("NUM\tADDRESS\tLAST\tFIRST\tMI    SSN        BALANCE    NEXT\n"); 
      printf("----------------------------------------------------------------\n\n"); 
      for(counter2=0;counter2<=counter1;counter2++)
      {
        printf("%d%5X\t%-12s\t%-9s\t%c   %9ld   %.2lf  ",counter2+1,tempptr,tempptr->lname,tempptr->fname,tempptr->initial,tempptr->socialnum,tempptr->balance);
        if(tempptr->next==NULL)
          printf("NULL\n");
        else
          printf("%5X\n",tempptr->next);
        tempptr=tempptr->next;
      }
      printf("\n\n");
    }
  }
  return 1;
}

hope this solves ya problem.

Thank you that helped alot but when i try to move the print part of my code inside my while loop where i read in the data it gives me errors. I am trying to get it where after it reads one line of the file which is one customer to print out the contents of the linked list so far then it should go back and read in the next line then print the contents of the linked list which would be 2 customers and so on.

here my error ridden code:

Code:

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

typedef struct customer 
{ 
  char fname[20]; 
  char lname[20]; 
  char initial;
  long socialnum;
  double balance;
  struct customer *next;
}CUSTOMER,LIST; 

int main() 
{ 
  FILE *infile,*infile2; 
  CUSTOMER *bankrecords;
  CUSTOMER *tempptr;
  CUSTOMER *tempptr2;
  CUSTOMER temprecord;
  LIST *bankrecords2;
  LIST *tempptr3;
  LIST *tempptr4;
  LIST temprecord2;
  int counter1,counter2,track=1;;

  bankrecords=NULL;

  infile=fopen("data.dat","r"); 
  if(infile == NULL)
  { 
    printf("Data file could not be opened.\n"); 
  }
  else
  {

// READ IN ALL THE FILE INTO THE LIST
    while(!feof(infile))
    {
      fscanf(infile,"%s %s %c %D %lf",temprecord.lname,temprecord.fname,&(temprecord.initial),&(temprecord.socialnum),&(temprecord.balance));
	
	  for(counter1=0;tempptr!=NULL;counter1++) {
	
		tempptr = bankrecords;
		printf("NUM\tADDRESS LAST\t     \tFIRST   MI    SSN        BALANCE    NEXT\n"); 
		printf("-------------------------------------------------------------------------------\n\n"); 
		track=1;
		for(counter2=0;counter2<=counter1;counter2++,track++) {
      
			printf("%d    %8X\t%-12s \t%-9s %1c   %9d   %-.2lf  ",track,tempptr,tempptr->lname,tempptr->fname,tempptr->initial,tempptr->socialnum,tempptr->balance);
			if(tempptr->next==NULL) 
				printf("NULL\n");
			else
				printf("%6X\n",tempptr->next);
			tempptr=tempptr->next;
		}
		printf("\n\n");
		}
	}
      if(bankrecords==NULL)
      {
        bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
        tempptr = bankrecords;
        tempptr->next=NULL;
      }
      else				// RECORDS ALREADY EXIST
      {
        tempptr = bankrecords;
        while((tempptr->next!=NULL) && (strcmp(tempptr->fname,temprecord.fname)<0))
          tempptr=tempptr->next;

        if((bankrecords==tempptr) && (strcmp(tempptr->fname,temprecord.fname)>0))	// RECORD BELONGS AT START OF LIST
        {
          tempptr2=tempptr;
          bankrecords = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr = bankrecords;
        }
        else				// RECORD IS SOMEWHERE IN MIDDLE OR END
        {
          tempptr2=tempptr->next;
          tempptr->next = (CUSTOMER *) malloc(sizeof(CUSTOMER));
          tempptr=tempptr->next;
        }
        tempptr->next=tempptr2;
      }

 // i tried to move this inside the while loop but it did no good    
      //COPY ALL DATA FROM TEMP RECORD TO NEW ONE
      strcpy(tempptr->fname,temprecord.fname);
      strcpy(tempptr->lname,temprecord.lname);
      tempptr->initial = temprecord.initial;
      tempptr->socialnum = temprecord.socialnum;
      tempptr->balance = temprecord.balance; 
    }
    fclose(infile);


    }
  

	return 0;
}