fix compile warning

aminimize/src/aminimize.cpp

@@ -26,7 +26,7 @@ int main(int argc, char** argv) {
 		if (argc == 2 && string("-h").compare(argv[1]) == 0) {
 			cout << "Automaton minimize.\nUsage: aminimize automaton.xml\n";
 			return -1;
-		} else if (argc == 1 || argc == 2 && string("--").compare(argv[1]) == 0) {
+		} else if (argc == 1 || (argc == 2 && string("--").compare(argv[1]) == 0)) {
 			automaton = AutomatonFactory::fromStdin();
 			if(!AutomatonFactory::isFSM(automaton)) {
 				cout << "Automaton minimize require deterministic finite automaton\n";