title: Basic C++ problem - Using variable within the class
body: <p>I have problem with C++ class. Is there have any way to reuse variable in the same class in the header file?</p>
  <p>I have try</p>
  <pre><code>PubSubClient mqttClient(this-&gt;secureClient);
  PubSubClient mqttClient(mqtt.secureClient);
  </code></pre>
  <p>but fail. Why?</p>
  <pre><code>#ifndef __MQTT_H_
  #define __MQTT_H_
  
  #include &quot;Arduino.h&quot;
  #include &quot;WiFi.h&quot;
  #include &quot;WiFiClientSecure.h&quot;
  #include &quot;PubSubClient.h&quot;
  
  class MQTT
  {
  public:
  
  bool initWiFi();
  String macAddress6btye(void);
  void callback(char *topic, byte *payload, unsigned int length);
  bool mqttConnect();
  bool mqttPublish(const String &amp;endPoint, const String &amp;payload);
  int getStrength(uint8_t points);
  
  private:
      WiFiClientSecure secureClient;
      PubSubClient mqttClient(this-&gt;secureClient);
  };
  
  #endif
  </code></pre>