#include <iostream>
#include <ctime>

void wait ( int seconds )
{
  clock_t endwait;
  endwait = clock () + seconds * CLOCKS_PER_SEC ;
  while (clock() < endwait) {}
}

class Timer
{
    private:
        time_t value;

    public:
        Timer() { value = time(NULL);};
        void add(int h, int m, int s);
        void show();
};

void Timer::add(int h, int m, int s)
{
    value -= s + m * 60 + h * 3600;
}

void Timer::show()
{
    std::cout << difftime(time(NULL), value);
}

int main()
{
    Timer T;
    T.add(0, 0, 30);
    wait(5);
    T.show();

    return 0;
}