public String toString(){
		String return_result = null;
		if(is_set_data()){
			return_result = set_data.toString();
		}
		else if(is_value_data()){
			return_result = CMath.double_to_str(value_data);
		}
		else if(is_struct_data()){
			return_result = "[";
			for(Map.Entry<String, CDataEntity> cur_data: struct_data.entrySet()){
				return_result += cur_data.getKey() + "=";
				return_result += cur_data.getValue().toString();
				return_result += ",";
			}
			if(return_result.length() != 1){
				return_result = return_result.substring(0, return_result.length() - 1);
			}
			return_result += "]";
		}
		else if(is_pointer_data()){
			return_result = pointer_data.toString();
		}
		return return_result;
	}