请问一下这个错误怎么修改啊

#include
using namespace std;
int main()
{
enum MonthsOfYear
{
Jan=1,Feb,Mar,Apr,May,Jun,Jul,Aug,Sept,Oct,Nov,Dec
};
int month, day, year;
cin >> month >> day >> year;
int DayinFeb;
if (year % 4 == 0)
DayinFeb = 29;
else if (year % 400 == 0)
DayinFeb = 29;
else if (year % 100 == 0)
DayinFeb = 28;
else
DayinFeb = 28;
int DayinMonths;
switch (month)
{
case Jan: case Mar: case May: case Jul: case Aug: case Oct: case Dec:
DayinMonths = 31;
break;
case Apr: case Jun: case Sept: case Nov:
DayinMonths = 30;
break;
default:
cout << "Invalid month: " << month << endl;
break;
}
if ((day < 1)||(day>DayinMonths))
cout << "Invalid day of month: " << day << endl;
else
cout << month << " / " << day << " / " << year << endl;
return 0;
}

没有报错。。。

报的什么错误