Function input arguments

[Jonnar]

I have an assignment for one of my classes in which we were given a few files to modify to create a program tokenizing text files and inserting the words into a linked list. One of the functions they gave us is this:

void tokenize_file(FILE *file, list_t *list)
{
    char *word;
    char buf[101];
    buf[100] = 0;

    while (!feof(file)) {
	/* Skip non-letters */
	fscanf(file, "%*[^a-zA-Z0-9'_]");
	/* Scan up to 100 letters */
	if (fscanf(file, "%100[a-zA-Z0-9'_]", buf) == 1) {
	    word = strdup(buf);
	    if (word == NULL)
		fatal_error("out of memory");
	    list_addlast(list, word);
	}
    }
}

What I am having problems with is to give the function the proper input. I am totally new in C programming and all the pointers etc are throwing me a bit off course here. I tried reading the FAQ, but it didn't help all that much with this specific problem.

What do I have to put in the main function to get this function to run as it should?
Edit: We are supposed to take input (name of the text file(s) to tokenize) from the command line

Thanks,
Jonnar

[vart]

you should read about fopen

and about NOT using feof to control loops

also I hope you free the allocated memory, when you remove word from the list

[Jonnar]

char *file = argv;
char *mode = "r";
FILE *read = fopen ( file, mode );

Ok, now the errors and warnings disappeared, so I am assuming the file is now open.

Next is my call on the function "tokenize_file".
It is supposed to look like this when I call it:

void tokenize_file(FILE *file, list_t *list)

But I have only got this so far, where read is the file I opened earlier:

tokenize_file(read);

How do I use a list as an argument?

[vart]

char *file = argv;
char *mode = "r";
FILE *read = fopen ( file, mode );

Ok, now the errors and warnings disappeared, so I am assuming the file is now open.

You should't. You should check the return value of fopen to be sure that file is opened

How do I use a list as an argument?

It depends on the processing of the list.
Probably - you should create variable of type list_t, initialize it in some way and pass pointer to this var

[Jonnar]

I still haven't figured out how to call the function

tokenize_file(FILE *file, list_t *list)

in a proper way.

My data structure looks like this (double-linked list):

struct node {
	struct node *next;
	struct node *prev;
	char word[100];
};

typedef struct node node_t;

I have opened a file, using

FILE *inputFile = fopen ( file, mode );

but how do I give the function the proper input? I keep getting "parse error before ..."

So my question: How do I give the function tokenize_file() the input it's supposed to get using my data structure (linked list) and a file?

[simguy]

BTW, your statement of "buf[100] = 0;" will only set the 100th member of the array to zero. Look at the function "memset" to intialize an array.

[Jonnar]

BTW, your statement of "buf[100] = 0;" will only set the 100th member of the array to zero. Look at the function "memset" to intialize an array.

I know. Unless the teachers made a faulty code it's supposed to be that way. I'm sure they have their reasons...

[Salem]

> while (!feof(file))
If your teacher also told you to do this, point them to our FAQ

[Jonnar]

> while (!feof(file))
If your teacher also told you to do this, point them to our FAQ

The whole function tokenize_file was provided by them... They also told us that char pointers and arrays are the same thing, which the FAQ also tells us is a no-no...

[Prelude]

>They also told us that char pointers and arrays are the same thing
Time to find some new teachers. The ones you have don't know C from a sack of steamed potatoes.

[anon]

Well, at least the function works. If fscanf doesn't do anything horrible if it is called after EOF, using feof to control the loop doesn't hurt either. See, we don't process the (empty) data that we'll read because of it.

buf[100] = 0; looks kinda stupid - fscanf inserts the null-terminator for you, otherwise any of this wouldn't work - but may-be it's a force of habit?

[ssharish2005]

void tokenize_file(FILE *file, list_t *list)

You could find out the actual paramter for this function from its prototype. From the above statment you can see that it is taking a file pointer which is nothing but the pointer to a file, i.e the return value of fopen which you have done before.

And the second is the address of the head node. In the your case the structure has been typedef to list_t. So some where in the main you have to declare the list pointer of type list_t.

ssharish2005