Thread: Inteface extending another interface

Hello every0x01,
I am trying to do 3 interfaces where,

A Controller interface extends Writeable and Readable interfaces and class I2CCommController implements Controller interface.

But I can't get my code compiled

Code:

class Writeable
{
    public:
        virtual ~Writeable() {}
        virtual bool writeByte(uint8_t byte) = 0;
        virtual uint8_t writeBytes(uint8_t* bytes, uint8_t offset, uint8_t length) = 0;
        virtual uint8_t writeBytes(uint8_t* bytes, uint8_t length) = 0;
        virtual uint8_t write(const char* string) = 0;
        virtual uint8_t write(int value) = 0;
        virtual uint8_t getAvailableForWrite() = 0;
};

Code:

class Readable
{
    public:
        virtual ~Readable() {}
        virtual bool readByte(uint8_t* byte) = 0;
        virtual uint8_t readBytes(uint8_t* buffer, uint8_t length) = 0;
        virtual uint8_t getAvailable() = 0;
};

Code:

class Controller : public Readable, public Writeable
{
    public:
        virtual ~Controller(){}


        virtual uint8_t open() = 0;    // Open I2C communication I/O Stream
        virtual void close() = 0;            // Close I2C communication I/O Stream
        virtual bool isOpened() = 0;
        //virtual Readable getReceiver() = 0;
        //virtual Writeable getWritter() = 0;
};

Problem is caused in a class I2CCommController which implements Controller interface

Code:

class I2CCommController : public Controller 
{
    private:
        uint16_t clockFrequency;
        uint8_t address;
        bool isOpen;
        volatile uint8_t status;
        volatile uint8_t slaveRW;
        volatile uint8_t sendStopBit;            // should the transaction end with a stop
        volatile uint8_t inRepStart;            // in the middle of a repeated start

        char controllerState;
        CircularQueue rxQueue;
        CircularQueue txQueue;
        static I2CCommController* i2cControllerPtr;
    
    public:
        I2CCommController(int _clockFrequency, uint8_t _address);
        I2CCommController();
        void setFrequency(uint16_t _clockFrequency);
        uint16_t getFrequency();
        void setAddress(uint8_t _address);
        uint8_t getAddress();
        
        void start();
        void stop();
        // Methods for Output Stream
        bool writeByte(uint8_t byte);
        uint8_t writeBytes(uint8_t* bytes, uint8_t length);
        uint8_t writeBytes(uint8_t* bytes, uint8_t length, const bool sendStop);
        uint8_t writeBytes(uint8_t* bytes, uint8_t offset, uint8_t length);
        uint8_t write(int value);
        uint8_t write(const char* string);
        uint8_t getAvailableForWrite();
        
        // Methods for Input Stream
        bool readByte(uint8_t* byte);
        uint8_t readBytes(uint8_t* buffer, uint8_t length);
        uint8_t readBytes(uint8_t* buffer, uint8_t length, const bool sendStop);
        uint8_t getAvailable();
        
        // Methods for I/O Stream Control
        uint8_t open();    // Open I2C communication I/O Stream
        void close();            // Close I2C communication I/O Stream
        bool isOpened();
        //Readable getReceiver();
        //Writeable getWritter();
        
        friend void TWI_vect(void);
        inline void interruptTWIHandler(voi

Writing without inheriting from Controller, and it compiles.

Code:

class I2CCommController

How is proper interface inheritance implemented in C++?

Originally Posted by GReaper

At the point when a variable is declared/defined, all pure virtual methods must've been implemented. Some method somewhere in there is still pure virtual, I presume.

In interface Controller do I have to rewrite virtual methods from Readable and Writeable interface since Controller inherits from both Readable and Writeable or I can leave implementation to a class which implements Controller interface without copying it?

Originally Posted by Salem

Your image is far too fuzzy to bother with the eye strain it causes.
Save it as a PNG, which is at least pixel accurate.
JPG quantisation just makes fine detail fuzzy.

Originally it was saved as PNG
https://s11.postimg.org/d1039cy2b/UML_Diagram_I2_C.pngupload pics