请大神解析怎么改
import java.util.*;public class sdf {
public static void main(String[] args){
Scanner in=new Scanner(System.in);
String a;
do {
System.out.println("请输入年份:");
int year=in.nextInt();
System.out.println("请输入月份:");
int month=in.nextInt();
int sum=0;
for(int i=1900;i<year;i++){
if(i%4==0&&i%100!=0||i%400==0){
sum+=366;
}else{
sum+=365;
}
}
for(int i=1;i<month;i++){
if(i==2){
if(year%4==0&year%100!=0||year%400==0){
sum+=29;
}else{
sum+=28;
}
}else{
if(i==4||i==6||i==9||i==11){
sum+=30;
}else{
sum+=31;
}
}
}
sum+=1;
int m=sum%7;
System.out.println("日\t一\t二\t三\t四\t五\t六");
for(int i=1;i<=m;i++){
System.out.print("\t");
}
for(int i=1;i<30;i++){
if(sum%7==6){
System.out.print(i+"\n");
}else{
System.out.print(i+"\t");
}
sum++;
System.out.print("否继续查询?(Y/N):");
a=in.next();
}while (a.equals("Y"));
}
}
}
