成熟的日期判斷

 #include <iostream>
using namespace std;
int main()
{
 int Evenday[12]={31,28,31,30,31,30,31,31,30,31,30,31};
 int year,day,month,nday=0,flag=1,i;
 for(;flag==1;)
 {
  cout<<"enter the year as a number:";
  cin>>year;
  cout<<"enter the month as a bumber:";
  cin>>month;
  cout<<"enter the day of this year as a number:";
  cin>>day;
  if(((month>2)*(year%4==0)*(year*100!=0)==0)||((month>2)*(year%4==0)*(year%100==0)*(year%400==0)==0))
  {
   Evenday[1]=29;
  }
  //判斷閏年給二月值
  if(day>Evenday[month-1]||(year>3000)||(year<1900)||(month>12)||(month<1))
  {
   cout<<"it is error data:";
   system("pause");
   return 0;
  }
  else flag=0;
 }
 for(i=0;i<month-1;i++)
 {
  nday+=Evenday[month];
 }
 nday+=day;
 cout<<"the total day is :"<<nday;
 system("pause");
 return 0;
}