万年历！

import java.util.Scanner;
public class yuan{
public static boolean runnian(int year){
if(year%4==0&&year%100!=0||year%400==0)
return true;
else
return false;
}
public static int day1(int year,int month){
int a[]={31,28,31,30,31,30,31,31,30,31,30,31};
if(runnian(year))
a[1]=29;
return a[month-1];
}
public static int day2(int year,int month,int day){
int i,sum=0;
for(i=1;i<month;i++){
sum+=day1(year,i);
}
sum+=day;
return sum;
}
public static int week1(int year,int month,int day){
int number=(year-1)+(year-1)/4-(year-1)/100+(year-1)/400+day2(year,month,day);
number%=7;
return number;
}

public static String Week2(int number){
switch(number)/*分类一周七天*/{
case 0: return "星期日";
case 1: return "星期一";
case 2: return "星期二";
case 3: return "星期三";
case 4: return "星期四";
case 5: return "星期五";
case 6: return "星期六";
default:return "错误!请您重新输入。";/*不符和上面七种情况的报错提示*/
}
}
public static void x1(int year,int month,int day){
int number=week1(year,month,day);
if(runnian(year))System.out.print("闰年");/*年份为闰年则输出“闰年“*/
else System.out.print("平年");
System.out.print(year+"年"+month+"月"+day+"日"+Week2(number)+"\n\n");/*按年 月 日输出结果*/
}
public static void x2(int year,int month){
int max,number,i,j=1;
max=day1(year,month);
number=week1(year,month,1);
System.out.println("星期日"+" "+"星期一"+" "+"星期二"+" "+"星期三"+" "+"星期四"+" "+" 星期五"+" "+"星期六");/*按照间隔打印日历*/
for(i=0;i<number;i++){
System.out.print(" ");
}
while(j<=max){
System.out.print(j+"    ");
if(i%7==6)
{
System.out.println();
}
i++;
j++;
}
System.out.println("\n");
}
public static int x3(int year,int month,int day){
if(year<0||month<1||month>12||day<1||day>day1(year,month))/*当输入值出现这些情况时*/
return 0;/*返回0*/
else
return 1;/*返回1*/
}
public static void nianli(int year){
int i;
System.out.println();
for(i=1;i<=12;i++)
{
if(runnian(year))System.out.print("闰年");
else System.out.print("平年");
System.out.print(year+"年"+i+"月\n\n");
}
}
public static void yueli(int year,int month){
if(runnian(year))
System.out.print("闰年");
else System.out.print("平年");
System.out.print(year+"年"+month+"月\n\n");
x2(year,month);
}
public static void rili(int year,int month,int day){
System.out.println();
x1(year,month,day);
}
public static void main(String[] args){
Scanner sc=new Scanner(System.in);
int year,month,day,a,b;
boolean i=true;
while(i){
System.out.print("\n\n\n\n");
System.out.print("             **********************************************************\n\n");
System.out.print("                             *                        *                   \n");
System.out.print("                               欢迎进入万年历查询系统                   \n");
System.out.print("                             *                        *                  \n\n");
System.out.print("             **********************************************************\n\n\n");
System.out.print("                  1 年历 2 月历 3 日历 4 退出\n");
System.out.print("                  请输入您的选择<1~4>,按回车键确定: ");
b=sc.nextInt();
switch(b){
case 1:/*选择1时*/
System.out.print("\n请输入您要查的年份: ");/*给出输入提示*/
year=sc.nextInt();/*输入查询的年份*/
a=x3(year,1,1);
if(a==0)
{
System.out.print("错误!请您重新输入。\n");/*输入植异常时报错*/
break;
}
nianli(year);
break;
case 2:/*选择二时*/
System.out.print("\n请输入您要查的年和月，年月之间用空格隔开: ");/*给出输入提示*/
year=sc.nextInt();
month=sc.nextInt();/*输入需要查询的年 月*/
a=x3(year,month,1);
if(a==0)
{
System.out.print("错误!请您重新输入。\n");
break;
}
yueli(year,month);
break;
case 3:/*选择3时*/
System.out.print("\n请输入您要查的年月日，年月日之间用空格隔开: ");/*给出输入提示*/
year=sc.nextInt();
month=sc.nextInt();
day=sc.nextInt();/*输入年 月 日*/
a=x3(year,month,day);
if(a==0)
{
System.out.print("错误!请您重新输入。\n");/*输入植异常时报错*/
break;
}
rili(year,month,day);
break;
case 4:
i=false;
default:
System.out.print("错误!请您重新输入。\n\n");
}
}
}

}