#include <stdio.h>
#include <string.h>
#define MAXLINE 1000

int find(char *pattern, FILE *fp, char *name);

int except, number; /* flags */

int main(int argc, char *argv[]) {
     char *pat;
     FILE *fp;
     char name[MAXLINE];
     int c, found = 0;

     while (--argc > 0 && (*++argv)[0] == '-')
	  while ((c = *++argv[0]))
	       switch (c) {
	       case 'x':
		    except = 1;
		    break;
	       case 'n':
		    number = 1;
		    break;
	       default:
		    printf("find: illegal option %c\n", c);
		    argc = 0;
		    found = -1;
		    break;
	       }
     if (argc == 1) {
	  pat = argv[0];
	  found += find(pat, stdin, "");
     } else if (argc > 1) {
	  pat = argv[0];
	  while (--argc >= 0 && *++argv != NULL) {
	       if ((fp = fopen(*argv, "r")) == NULL) {
		    fprintf(stderr, "error: unable to open file: %s\n", *argv);
		    exit(1);
	       }
	       strcpy(name, *argv);
	       strcat(name, ": ");
	       found += find(pat, fp, name);
	  }
     } else
	  printf("Usage: find -x -n pattern [FILES ...]\n");

     return found;
}

int find(char *pat, FILE *fp, char *name) {
     int found, lineno;
     char line[MAXLINE];
 
     found = lineno = 0;
     while(fgets(line, MAXLINE, fp) > 0) {
	  lineno++;
	  if ((strstr(line, pat) != NULL) != except) {
	       printf("%s", name);
	       if (number)
		    printf("%d: ", lineno);
	       printf("%s", line);
	       found++;
	  }
     }
     
     return found;
}