Demo: can now read from stdin

demo.c

@@ -57,11 +57,15 @@ int main(int argc, char *argv[]) {
 		exit(EXIT_SUCCESS);
 	}
 
+	if (strcmp(argv[1], "-") == 0) {
+		f = stdin;
+	} else {
 		f = fopen(argv[1], "r");
 		if (f == NULL) {
 			fprintf(stderr, "Failed to open file `%s`\n", argv[1]);
 			exit(EXIT_FAILURE);
 		}
+	}
 
 	while (1) {
 		char buf[BUFSIZ];