java输入年月日判断是那年的第几天

输入年月日判断是一年中的第几天

实验课时做的  ,看到有人交流C的实现  我觉得用switch() 会简洁一点   未加入验证

没有日期的验证 比如说 13月33号  有时间再弄

import java.io.*;
public class SuanTianShu{
static public void main(String[] args){
    int year,month,day;
    int days =0;
    boolean luinian = false;
    System.out.print("input the year:");
  year = IO.getInt();
      System.out.print("input the month:");
  month = IO.getInt();
      System.out.print("input the day:");
  day = IO.getInt();
   if(year%400 ==0 || (year%4==0&&year%100!=0)){

      luinian = true;
  }
  for(int i = 1;i<month;i++){
  switch(i){
      case 1:case 3:case 5:case 7:case 8:case 10:case 12: days += 31;break;
      case 2: days += 28;break;
      case 4:case 6:case 9:case 11: days += 30;break;
  }
  }
  if(luinian&&month>2){
      days++;
  }
  days+=day;
    System.out.println(year+"年"+month+"月"+day+"日是"+year+"的第"+days+"天");
}
}

class IO{

    public static int getInt(){
        DataInputStream dis=new DataInputStream(System.in);
        int value=0;
        try{
            String str=dis.readLine();
            value=Integer.parseInt(str);
            
        }catch(IOException e){
            e.printStackTrace();
        }
        return value;
    }
}