万年历初次版本

import java.util.Scanner;
class  zuoye_2
{
    public static int day (int i)
        {
                int r1 = 0;
                int r2 = 0;
                for (int j=1900;j<i ;j++ ){
                    if (j%4==0&&j%100!=0||j%400==0){
                        r1++;
                    }
                    else{
                        r2++;
                    
                    }
                }
        return (r1*366+r2*365);
    }
    public static int ri(int a,int c){
        int b = 0;
        if (c%4==0&&c%100!=0||c%400==0){
            switch(a){
                case 1 :
                    b = 0;
                break;
                case 2 :
                    b=31;
                break;
                case 3 :
                    b = 60;
                break;
                case 4 :
                    b = 91;
                break;
                case 5 :
                    b = 121;
                break;
                case 6 :
                    b = 152;
                break;
                case 7 :
                    b = 182;
                break;
                case 8 :
                    b = 213;
                break;
                case 9 :
                    b =244 ;
                break;
                case 10 :
                    b = 274;
                break;
                case 11 :
                    b =305;
                break;
                case 12 :
                    b = 335;
            }
        }
        else{
            switch(a){
                case 1 :
                    b = 0;
                break;
                case 2 :
                    b=31;
                break;
                case 3 :
                    b = 59;
                break;
                case 4 :
                    b = 90;
                break;
                case 5 :
                    b = 120;
                break;
                case 6 :
                    b = 151;
                break;
                case 7 :
                    b = 181;
                break;
                case 8 :
                    b = 212;
                break;
                case 9 :
                    b =243 ;
                break;
                case 10 :
                    b = 273;
                break;
                case 11 :
                    b =304;
                break;
                case 12 :
                    b = 334;
            }
        }
        return b;
    }
    public static void shuChu(int i,int j,int z)
    {
        int a1 =0;
        int a3 = i;
        for(int a = 0;a<i ;a++)
        {
            System.out.print(" "+"\t");
        }
        if (z%4==0&&z%100!=0||z%400==0){
            switch(j)
            {
                default:
                    a1=31;
            break;
                case 2:
                    a1=29;
                break;
                case 4:
                case 6:
                case 9:
                case 11:
                    a1=30;

            }
        }
        else{
            switch(j){
                default:
                    a1=31;
                break;
                case 2:
                    a1=28;
                break;
                case 4:
                case 6:
                case 9:
                case 11:
                    a1=30;
            }
        }
        for(int a2=1;a2<=a1;a2++)
        {
                System.out.print((a2)+"\t");
                    a3++;
                if(a3%7==0){
                    System.out.println();
                }
        }
    }
    public static void main(String[] args) 
    {
        
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入想要查询的年份");
        int y= sc.nextInt();
        System.out.println("请输入想要查询的月份");
        int m1=sc.nextInt();
        System.out.println("星期一"+"\t"+"星期二"+"\t"+"星期三"+"\t"+"星期四"+"\t"+"星期五"+"\t"+"星期六"+"\t"+"星期日"+"\t");
        int d2=day(y);
        int d1=ri(m1,y);
        int d=0;
        d=d1+d2;
        
        int yu = d%7;
        shuChu(yu,m1,y);
        System.out.println(d);
    }
}