324定义一个日期类Date，该对象存放一个日期，可以提供的操作有：
Voidpri
tDate显示日期VoidGetYear取年的值VoidGetMo
th取月的值VoidGetDay取日的值VoidSetDatei
tYi
tmi
td设置日期值i
cludeiostreami
cludestri
gusi
g
amespacestdclassDateprivatestri
gyearstri
gmo
thstri
gdaypublicvoidPri
tDatevoidGetYearvoidGetMo
thvoidGetDayvoidDatePri
tDatecoutyear