public void AddMonth(int m)
{
if (m < 0)
{
SubstractMonth(-m);
}
else
{
if (clock == null)
{
setClock();
}
for (int i = m; i > 0; i--)
{
if (month.Month_number == clock.GetNumberOfMonths())
{
AddYear(1);
}
month = month.next_month;
}
}
}