输入两个日期（年 月 日 年 月 日）， 输出这两个日期之间差多少天

 1 #ifndef __FUN_H__
 2 #define __FUN_H__
 3 #include <stdio.h>
 4 #include <stdlib.h>
 5 
 6 unsigned days_in_year(unsigned y, unsigned m, unsigned d);
 7 int is_leap_year(unsigned y);
 8 #endif
 9 
10 //给定两个日期，求这两个日期相隔多少天？
11 #include "func.h"
12 
13 int main(int argc, char *argv[])
14 {
15     unsigned y1, m1, d1, y2, m2, d2, i, n = 0;
16     int res;
17 
18     while (fflush(stdin), (res = scanf("%d%d%d%d%d%d", &y1, &m1, &d1, &y2, &m2, &d2)) != EOF)
19     {
20         n = 0;
21         if (y1 != y2)
22         {
23             if (is_leap_year(y1))
24                 n += 366 - days_in_year(y1, m1, d1);
25             else 
26                 n += 365 - days_in_year(y1, m1, d1);
27             for ( i = y1 + 1; i < y2; i++)
28             {
29                 if( is_leap_year(i) )
30                     n += 366;
31                 else
32                     n += 365;
33             }
34             n += days_in_year(y2, m2, d2);
35         }
36         else
37             n = days_in_year(y2, m2, d2) - days_in_year(y1, m1, d1);
38         printf("以上两个日期相隔%d天\n", n);
39     }
40     system("pause");
41     return 0;
42 }
43 
44 
45 unsigned days_in_year(unsigned y, unsigned m, unsigned d)
46 {
47     unsigned n = 0, i;
48     unsigned months[13] = {0,31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
49 
50     if(is_leap_year(y))
51         months[2] = 29;
52     else 
53         months[2] = 28;
54     for ( i = 1; i < m; i++)
55         n += months[i];
56     n += d;
57     return n;
58 }
59 
60 
61 int is_leap_year(unsigned y)
62 {
63     if((y % 4 == 0 && y % 100 != 0) || y % 400 == 0)
64         return 1;
65     else 
66         return 0;
67 }