void showTime() const;

     Clock& operator ++();

     Clock operator ++(int);

 private:

     int hour,minute,second;

 };

 Clock::Clock(int hour,int minute,int second){

     if(<=hour&&hour<&&<=minute&&minute<&&<=second&&second<)

        {

            this->hour=hour;

            this->minute=minute;

            this->second=second;

        }

     else

         cout<<"Time error!"<<endl;

 }

 void Clock::showTime() const

 {

     cout<<hour<<":"<<minute<<":"<<second<<endl;

 }

 Clock& Clock::operator ++()

 {

     second++;

     if(second>=)

     {

         second-=;

         minute++;

         if(minute>=)

         {

             minute-=;

             hour=(hour+)%;

         }

     return *this;

     }

 }

 Clock Clock::operator ++(int)

 {

     Clock old=*this;

     ++(*this);

     return old;

 }

 int main()

 {

     Clock myClock(,,);

     cout<<"First time output:";

     myClock.showTime();

     cout<<"Show myClock++:   ";

     (myClock++).showTime();

     cout<<"Show ++myClock:   ";

     (++myClock);

     myClock.showTime();

     return ;

 }