编程实现，对输入的年、月、日，给出该天是该年的第几天。提示：用for语句和switch语句。

java编程实现，对输入的年、月、日，给出该天是该年的第几天。提示：用for语句和switch语句。(你刚发来的代码，一运行就出现个364)麻烦看看怎么回事~！~

//对输入的年，月、日，给出这天是这年的第几天
import java.io.*;
public class days{
public static void main(String[] args) throws IOException{
BufferedReader Reader=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Please input the year: ");
int year=Integer.parseInt(Reader.readLine());
System.out.println("Please input the month: ");
int month=Integer.parseInt(Reader.readLine());
System.out.println("Please input the day: ");
int day=Integer.parseInt(Reader.readLine());
int daynum=0,daysum=0;
for(int i=1;i<month;i++)
{
switch(i){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
daynum=31;break;
case 4:
case 6:
case 9:
case 11:
daynum=30;break;
case 2:
if(year%4==0&&year%100!=0||year%400==0)
daynum=29;
else
daynum=28;
break;
}
daysum+=daynum;
}
daysum+=day;
System.out.print("这天是这年的第"+daysum+"天");
}
}