public static String getCommandType(String command){
		if(checkInList(INPUT_ADD, command)) {
			return TYPE_ADD;
		} else if(checkInList(INPUT_MODIFY, command)) {
			return TYPE_MODIFY;
		} else if(checkInList(INPUT_DELETE, command)) {
			return TYPE_DELETE;
		} else if(checkInList(INPUT_DISPLAY, command)) {
			return TYPE_DISPLAY;
		} else if(checkInList(INPUT_SEARCH, command)) {
			return TYPE_SEARCH;
		} else if(checkInList(INPUT_UNDO, command)) {
			return TYPE_UNDO;
		} else if(checkInList(INPUT_EXIT, command)) {
			return TYPE_EXIT;
		} else {
			return TYPE_ERROR;
		}
	}