//Adding the date (if valid) to the array in a specific place in the array
int Calendar::setDate(const MyDate &newDate, int num)
{
    if ((num < 1) || (num > 30))
        return -1;

    m_myDate[num - 1] = new MyDate;
    *m_myDate[num - 1] = newDate;

    m_cnt++;

    return 0;