Y
N
The next day is :year.month+1.1
month==4 || month==6 || month==9 || month==11
The next day is :year.month.day+1
The date is not right!
month==2
month==12
The next day is :year+1.1.1
day==29
end
please enter again!
The next day is:year.month+1.1
day==31
day==30
day==28
The next day is:year.month.day+1
year<=2050 && year>=1912
day<=29 && day>=1
begin
year%400==0 || (year%4==0 && year%100!=0)
day<=30 && day>=1
month==1 || month==3 || month==5 || month==7 || month==8 || month==10
day>=1 && day<=30
