Linked List Initialisation

Question

i am trying to update a previous program i was practicing on, by using linked lists, to see how they work. I have a txt file that includes the number of seats of a bus. Reading this bus.txt file is followed by dynamic allocation of memory for the specific linked list and numberofseats..(For example 45 seats). I write the following code, just to test how it works, and i am trying to put A in each passenger's fullname, 0 for the phonenr etc.. When i try to print the 45 seats to see if it works ok, i get an infinite loop and A's are printed for ever.. What am i missing?

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

int i,j,numberofseats,temp;     
char platenr[8],selection;      
char firstname[20],lastname[20]; 
char phone[11];                  
char *p;                         

typedef struct psg               
    {
    char fullname[40];
    unsigned short phonenr[10]; 
    unsigned int seatnr;        
    struct psg *next
    }PASSENGERS;                


PASSENGERS* readfile(char *platenr, int *seatnr)
    {
    char buff[60];
    FILE *businfo;
    businfo = fopen ("bus.txt","r");
    if (businfo == NULL)
        {
        printf("Error Opening File, check if file bus.txt is present");
        exit(1);
        }
    else                                            
        {
        fscanf(businfo,"%s %d",platenr, seatnr);  
        printf("Bus Licence plate Nr is: %s, and Number of Seats is: %d", platenr, *seatnr); 
        PASSENGERS *p = malloc(*seatnr * sizeof(PASSENGERS)); 
        if (p==NULL)            
        {
            puts("Unable to allocate memory");
            exit(1);
        }
        return p;                                                      
        }

    }



int main()
{
PASSENGERS *passenger, *tmp, *start=NULL;
passenger = readfile(platenr,&numberofseats);
for (i=0;i<numberofseats;i++)
    {
    passenger->next=NULL;
    strcpy (passenger->fullname,"A");
    passenger->seatnr=i+1;
    for (j=0;j<10;j++)
        passenger->phonenr[j]=0;
    if (start==NULL)
        start=passenger;
    else{
        tmp=start;
    while (tmp->next !=NULL) tmp=tmp->next;
    tmp->next=passenger;
    }
    }
tmp=start;
while(tmp!=NULL)
{
    printf ("%s",tmp->fullname);
    tmp=tmp->next;
}
}

Answer 1

Thanks everyone! I have changed my code, to make it a linked list according to your comments, and it works outside of a function. However when trying to pass it inside a function i have some problems still..

#include <stdio.h>              
#include <string.h>             
#include <stdlib.h>             
int i,j,numberofseats,temp;     
char platenr[8],selection;      
char firstname[20],lastname[20]; 
char phone[11];                  
char *p;                         

typedef struct psg                   {
    char fullname[40];
    unsigned short phonenr[10]; 
    unsigned int seatnr;        
    struct psg *next
    }PASSENGERS;                

void readfile(char *platenr, int *seatnr, PASSENGERS passenger,PASSENGERS tmp,  PASSENGERS start)
    {
    char buff[60];
    FILE *businfo;
    businfo = fopen ("bus.txt","r");
    if (businfo == NULL)
        {
        printf("Error Opening File, check if file bus.txt is present");
        exit(1);
        }
    else                                                                
        {
        fscanf(businfo,"%s %d",platenr, seatnr);      
        printf("Bus Licence plate Nr is: %s, and Number of Seats is: %d", platenr, *seatnr); 
        for (i=0;i<numberofseats;i++)
        {
        passenger  = (PASSENGERS *) malloc (sizeof(PASSENGERS));
        if (p==NULL)            
            {
            puts("Unable to allocate memory");
            exit(1);
            }
        passenger->next=NULL;
        strcpy (passenger->fullname,"A");
        passenger->seatnr=i+1;
        for (j=0;j<10;j++)
            passenger->phonenr[j]=0;
        if (start==NULL)
            start=passenger;
        else{
            tmp=start;
        while (tmp->next !=NULL) tmp=tmp->next;
        tmp->next=passenger;
            }
        }
        tmp=start;
        while(tmp!=NULL)
            {
            printf ("%s",tmp->fullname);
            tmp=tmp->next;
            }

        return p;                                                       
        }

    }



int main()
{
PASSENGERS *passenger, *tmp, *start=NULL;
readfile(platenr,&numberofseats, passenger, tmp, start,);

}