Data Conversion [Time 24 to Time 12]

#include<iostream>
#include<string>
using namespace std;

class Time24{
    private:
        int hour, min, sec;
    public:
        Time24():hour(0),min(0),sec(0){}
        Time24(int a, int b, int c):hour(a),min(b),sec(c){}
        ~Time24(){}
        int getHour(){return hour;}
        int getMin(){return min;}
        int getSec(){return sec;}
        void display(){
            cout << hour << ":" << min << ":" << sec << endl;
        }
        // conversion operator Time24 -> int
        operator int(){
            return (hour*3600+min*60+sec);
        }
        // 1-arg constructor int -> Time24
        Time24(int s){
            hour = s/3600;
            min = s/60 - (hour*60);
            sec = s - (min*60) - (hour*3600);
        }
        operator Time12(){
            int h = hour;
            int m = min;
            int s = sec;
            bool day;
            if(h>12){
                h = h - 12;
                day = true;
            }
            else if(h==12){
                day = true;
            }
            else{
                day = false;
            }

            if(h == 0)
                h = 12;
            return Time12(h,m,s,day);

        }

};

class Time12{
    private:
        int hour, min, sec;
        bool day; // day = false = am, day = true = pm
    public:
        Time12():hour(0),min(0),sec(0),day(false){}
        Time12(int a, int b, int c, bool d):hour(a),min(b),sec(c),day(d){}
        ~Time12(){}
        int getHour(){return hour;}
        int getMin(){return min;}
        int getSec(){return sec;}
        bool getDay(){return day;}
        void display(){
            string str;
            str = (day==false) ? "am" : "pm";
            cout << hour << ":" << min << ":" << sec << " " << str << endl;
        }
        // 1-arg constructor Time24 -> Time12
        Time12(Time24 t){
            hour = t.getHour();
            min = t.getMin();
            sec = t.getSec();
            if(hour>12){
                hour = hour - 12;
                day = true;
            }
            else if(hour==12){
                day = true;
            }
            else{
                day = false;
            }

            if(hour == 0)
                hour = 12;

        }

};

int main(){
    Time24 t1(23,0,1);
    int seconds = static_cast<int>(t1); // explicit casting
    cout << "Equivalent Seconds: " << seconds << endl;
    Time24 t2(3670);
    t2.display();
    Time12 t3(t1); // invoke 1-arg constructor in Time12 class
    t3.display();

    return 0;
}