输入某年某月某日，判断这一天是这一年的第几天详解编程语言

 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 }