#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <sys/types.h>

#define MAX_TAG_SIZE 1024

/* macro that states whether a char is a ``blank'' */
#define IS_BLANK(c) ( (c == 0x09) || (c == '\n') || (c == 0x0b) || (c == 0x0c) || (c == ' ') )

/* macro that states whether a char is a ``valid tag'' one */
#define VALID_TAG_CHAR(c) ( ( (c >= 'A') && (c <= 'Z')) || ( (c >= 'a') && (c <= 'z')) || ( (c >= '0') && (c <= '9')) || (c == '-') || (c == '_') )





... tag_insert (...);



#define FSM_START 0
#define FSM_GETTAG_EMPTY 1
#define FSM_GETTAG 2
#define FSM_WAITFOREND 3

int main (int argc, char **argv)
{
	char *filename;
	FILE *fp;
	char c;
	int fsm_state;
	int line_number;

	/* parse the arguments */
	if (argc == 1) {
		filename = NULL;
	} else if (argc == 2) {
		filename = argv[1];
	} else {
		fprintf (stderr, "Error: Too many parameters\n");
		exit(1);
	}

	if ( filename == NULL ) {
		fp = stdin;
	} else {
		fp = fopen(filename, "r");
		if (fp == NULL) {
			printf ("Error while opening file %s - %s\n", filename,
					strerror(errno));
			exit (1);
		}
	}


	fsm_state = FSM_START;
	line_number = 1;

	while (! feof(fp) ) {
		c = tolower(fgetc(fp));

		/* your code here */

	}

	/* your code here */
	return 0;
}


/* your code here */