输入某年某月某日，判断这一天是这一年的第几天？

 1 package com.li.FiftyAlgorthm;
 2 
 3 import java.util.Scanner;
 4 
 5 /**
 6  * 题目：输入某年某月某日，判断这一天是这一年的第几天？
 7  * 程序分析：以7月9日为例，应该先把前两个月的加起来，然后再加上9天即本年的第几天，特殊情况，闰年且输入月份大于3时需考虑多加一天。
 8  * 
 9  * @author yejin
10  */
11 public class YearMonthDay {
12     public static void main(String[] args) {
13         int year, month, day;
14         int days = 0;
15         int d = 0;
16 
17         YearMonthDay fymd = new YearMonthDay();
18 
19         System.out.print("Input the year:");
20         year = fymd.input();
21         System.out.print("Input the month:");
22         month = fymd.input();
23         System.out.print("Input The Day:");
24         day = fymd.input();
25 
26         if (year < 0 || month < 0 || month > 12 || day < 0 || day > 31) {
27             System.out.println("Input error, please run this program again!");
28             System.exit(0);
29         }
30         for (int i = 1; i < month; i++) {
31             switch (i) {
32             case 1:
33             case 3:
34             case 5:
35             case 7:
36             case 8:
37             case 10:
38             case 12:
39                 days = 31;
40                 // d += days;
41                 break;
42             case 4:
43             case 6:
44             case 9:
45             case 11:
46                 days = 30;
47                 // d += days;
48                 break;
49             case 2:
50                 if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0)) {
51                     days = 29;
52                 } else {
53                     days = 28;
54                 }
55                 // d += days;
56                 break;
57             }
58 
59             d += days;
60 
61         }
62         System.out.println(year + ":" + month + ":" + day + "是今年的第" + (d + day)
63                 + "天。");
64     }
65 
66     public int input() {
67         int value = 0;
68         Scanner s = new Scanner(System.in);
69         value = s.nextInt();
70         return value;
71     }
72 }