int main()
{
printf("%d\n", previous_day(Monday));
printf("%d\n", next_day(Sunday));
printf("%d %d", increment_day(Thursday, 4), increment_day(Monday, -4));
return 0;
}
TimeWithDate& TimeWithDate::operator-= (time_t t)
{
t -= this->seconds();
int d = 0;
while(t < 0)
{
d++;
t += SECS_IN_A_DAY;
}
for (int i = 0; i < d; ++i)
previous_day();
return *this = TimeWithDate(year, month, day, t);
}