2021-09-28

import java.util.Scanner;
public class 算日子{
    public static void main(String[] args){
    	boolean flag=true;
    	int year=0;
    	int month=0;
    	int date=0;
    	System.out.println("欢迎使用本系统！");
    	System.out.println("本系统支持计算某一天在一年中的第几天。");
        System.out.print("请输入要计算的年份：");
        Scanner userInput=new Scanner(System.in);
        while (flag) {	
        	year=userInput.nextInt();
            if (year<1){
                System.out.println("您输入的年份不合法，请重新输入：");
                flag=true;
            }else {
            	flag=false;
            }
        }
        flag=true;
        System.out.print("输入月份：");
        while (flag) { 
            month=userInput.nextInt();
            if (month<1||month>12){
                System.out.println("您输入的月份不合法，请重新输入：");
                flag=true;
            }else {
            	flag=false;
            }
        }    
        flag=true;    
        System.out.print("输入日期：");
        int a []={31,29,31,30,31,30,31,31,30,31,30,31};
        while (flag) {
            date=userInput.nextInt();           
            if (isRunNian(year)){
                if (date<1||date>a[month-1]){
                    System.out.println(year+"年"+month+"月只有"+a[month-1]+"天，输入的日期不合法，请重新输入：");
                    flag=true;
                }else {
                	flag=false;
                }
            }
            else{
                a[1]=28;
                if (date<1||date>a[month-1]){
                    System.out.println(year+"年"+month+"月只有"+a[month-1]+"天，输入的日期不合法，请重新输入：");
                    flag=true;
                }else {
                	flag=false;
                }
            }
        }        
        if (isRunNian(year)){
          System.out.println(year+"年为闰年");
          int sum=0;
          if (month==1){
              System.out.print(year+"年"+month+"月"+date+"日为该年的第"+date+"天");
              return;
          }else{
              for (int i=1;i<=month-1;i++){
                  sum+=a[i-1];
              }
          }
          sum+=date;