Merge "Initialize mFp file pointer to null" into main

  private:

    int mSockfd = -1;

    FILE* mFp;

    FILE* mFp = nullptr;

    bool mIsIpV4 = true;                                         // By default, set to IPV4

    int mPort = 12345;                                           // default port

    int mBufferSize = 188;                                       // bytes