Linked List

[c beginner]

I am trying to read data from a data file. But I don't know why the last record is failed to display.

My datafile structure is like this:
1
Name1
Credit1
2
Name2
Credit2
3
Name3
Credit3

The last record (3 Name3 Credit3) is always missing in the display. Would you please give me some idea ??

My source code is:

struct student *ReadData(FILE* inFile)
{
struct student *head;
struct student *ptr1,*ptr2;
n=0;
ptr1=ptr2=(struct student *)malloc(LEN);

fscanf(inFile,"%d\n%s\n%d",&ptr1->studentID,ptr1->studentname, &ptr1->credit);
head=NULL;

while(ptr1->studentID!=0)
{
n=n+1;
if(n==1){
head=ptr1;
}
else{
ptr2->next=ptr1;
}
ptr2=ptr1;
ptr1=(struct student *)malloc(LEN);
fscanf(inFile,"%d\n%s\n%d",&ptr1->studentID,ptr1->studentname, &ptr1->credit);

}


ptr2->next=NULL;

fclose(inFile);
return(head);
}


void DisplayRec(head)
struct student *head;
{
struct student *ptr;
printf("StudentID StudentName Credits\n");


ptr=head;
if(head!=NULL)

do{
printf("%5d%17s%11d\n",ptr->studentID,ptr->studentname,ptr->credit);
ptr=ptr->next;
}
while(ptr!=NULL);
}

Thank you for giving help !!!!

[c beginner]

Sorry, the condition of the while loop should be

while(!feof(inFile)){

.....



}


not while(ptr->studentID!=0)


Thanks.

[Salem]

> while(!feof(inFile)){
This has to be one of the most common mistakes

feof() does not become true UNTIL a read function (like fscanf) has failed to read something.

This means that the last fscanf in your loop really did not read any data, and just returned EOF (which I guess you didn't test either).

Try this

struct student *ReadData(FILE* inFile) 
{ 
    struct student *head = NULL; // the list
    struct student *ptr1; // the next node
    struct student temp; // file data

    while ( fscanf(inFile,"%d\n%s\n%d",
            &temp.studentID, temp.studentname, &temp.credit ) != EOF ) {
        // new node
        ptr1 = malloc( sizeof( struct student ) );
        ptr1->studentID = temp.studentID;
        // etc
        // now link ptr1 into the list starting at head
}

[c beginner]

Many Thanks for Giving Help!

I will keep trying!!

[Quantrizi]

What compiler are you using anyhow?