class Interface{
public:
    Interface(){};
    virtual States Action(States s, uint8_t key) = 0;
    virtual uint8_t ReadKey() = 0;
};

class ob : public Interface{
public:
    ob(){
        Text.ClrScr();
        Text.GoTo(0,0);
        Text.Write("constructor ob \n");
    };

    virtual States Action(States s, uint8_t key){
        Text.ClrScr();
        Text.GoTo(0,0);
        Text.Write("ob override Action\n");
        return sInputWindow;
    };

    virtual uint8_t ReadKey(void){
        return 'b';
    };

};

class oa : public Interface {
public:
    oa(){
        Text.ClrScr();
        Text.GoTo(0,0);
        Text.Write("constructor oa \n");
    };

    virtual States Action(States s, uint8_t key){
        Text.ClrScr();
        Text.GoTo(0,0);
        Text.Write("oa override Action\n");
        return sMainWindow;
    };

    virtual uint8_t ReadKey(void){
        return 'a';
    };
};
int main(void)
{
    oa a;
    ob b;

    States s = sMainWindow;

    Interface* obj;

    obj  = &a;

    while(1){
        s = obj->Action(s, obj->ReadKey());
        if( s == sMainWindow){
            obj = &b;
        }else{
            obj = &a;
        }
        delay(0x2fffff);
    };


};