Can anybody pls explain me how setsecond(getsecond() + 1) working in void time::tick()?

#ifndef TIME_HPP
#define TIME_HPP

class Time
{
private:
    int hour;
    int minute;
    int second;

public:
    explicit Time(int = 0, int = 0, int = 0);
    ~Time();

    // Setters
    void setTime(int, int, int);
    void setHour(int);
    void setMinute(int);
    void setSecond(int);

    // Getters
    int getHour() const;
    int getMinute() const;
    int getSecond() const;

    void printStandard() const;
    void printUniversal() const;
    void tick();
};

#endif

#include <ctime>
#include <iomanip>
#include <iostream>
#include "Time.hpp"

Time::Time(int hr, int min, int sec)
{
    setTime(hr, min, sec);
}

Time::~Time() {}

void Time::setTime(int h, int m, int s)
{
    setHour(h);
    setMinute(m);
    setSecond(s);
}

void Time::setHour(int h)
{
    if (h >= 0 && h < 24)
        hour = h;
    else
        throw std::invalid_argument("hour must be 0-23");
}

void Time::setMinute(int m)
{
    if (m >= 0 && m < 60)
        minute = m;
    else
        throw std::invalid_argument("minute must be 0-59");
}

void Time::setSecond(int s)
{
    if (s >= 0 && s < 60)
        second = s;
    else
        throw std::invalid_argument("second must be 0-59");
}

int Time::getHour() const { return hour; }
int Time::getMinute() const { return minute; }
int Time::getSecond() const { return second; }

void Time::printStandard() const
{
    std::cout << ((getHour() == 0 || getHour() == 12) ? 12 : getHour() % 12)
              << ":" << std::setfill('0') << std::setw(2) << getMinute() << ":"
              << std::setw(2) << getSecond() << (hour < 12 ? " AM" : " PM");
}

void Time::printUniversal() const
{
    std::cout << std::setfill('0') << std::setw(2) << getHour() << ":"
              << std::setw(2) << getMinute() << ":" << std::setw(2)
              << getSecond();
}
<pre>void Time::tick()
{
    if (getSecond() < 59)
        setSecond(getSecond() + 1);
    else
    {
        setSecond(0);
        if (getMinute() < 59)
            setMinute(getMinute() + 1);
        else
        {
            setMinute(0);
            if (getHour() < 23)
                setHour(getHour() + 1);
            else
            {
                setHour(0);
                setMinute(0);
                setSecond(0);

         }
        }
    }
};

#include <iostream>
#include "Time.hpp"

int main(int argc, char const *argv[])
{
    Time t1(23, 59, 58);

    std::cout << "t1: ";

    t1.printUniversal();

    std::cout << std::endl;

    for (int i = 0; i < 100; ++i)
    {
        t1.tick();

        if (i % 10 == 0)
        {
            t1.printUniversal();

            std::cout << " ";

            t1.printStandard();

            std::cout << std::endl;
        }
    }

    return 0;
}

What I have tried:

<pre>void Time::tick()
{
    if (getSecond() < 59)
        setSecond(getSecond() + 1);
    else
    {
        setSecond(0);
        if (getMinute() < 59)
            setMinute(getMinute() + 1);
        else
        {
            setMinute(0);
            if (getHour() < 23)
                setHour(getHour() + 1);
            else
            {
                setHour(0);
                setMinute(0);
                setSecond(0);

         }
        }
    }
};

#include <iostream>
#include "Time.hpp"

int main(int argc, char const *argv[])
{
    Time t1(23, 59, 58);

    std::cout << "t1: ";

    t1.printUniversal();

    std::cout << std::endl;

    for (int i = 0; i < 100; ++i)
    {
        t1.tick();

        if (i % 10 == 0)
        {
            t1.printUniversal();

            std::cout << " ";

            t1.printStandard();

            std::cout << std::endl;
        }
    }

    return 0;
}