time.h允许闰年C

Question

我正在寻找一种方法来找到两个日期之间的差异.解决方案需要考虑闰年.请参阅下面的两个代码块.2012年是闰年,而2013年则没有,因此我无法理解为什么两个项目都会输出"32天的差异".当time.h确实考虑到闰年时,他们肯定会有所不同吗？

首先:

#include <stdio.h>  
#include <time.h>       
int main ()
{
  struct tm start_date;
  struct tm end_date;
  time_t start_time, end_time;
  double days;

  start_date.tm_hour = 0;  start_date.tm_min = 0;  start_date.tm_sec = 0;
  start_date.tm_mon = 2; start_date.tm_mday = 1; start_date.tm_year = 112;

  end_date.tm_hour = 0;  end_date.tm_min = 0;  end_date.tm_sec = 0;
  end_date.tm_mon = 3; end_date.tm_mday = 1; end_date.tm_year = 112;

  start_time = mktime(&start_date);
  end_time = mktime(&end_date);

  days = difftime(end_time, start_time) / 86400;

  printf ("%.f days difference\n", days);

  return 0;
}

第二:

#include <stdio.h>  
#include <time.h>       
int main ()
{
  struct tm start_date;
  struct tm end_date;
  time_t start_time, end_time;
  double days;

  start_date.tm_hour = 0;  start_date.tm_min = 0;  start_date.tm_sec = 0;
  start_date.tm_mon = 2; start_date.tm_mday = 1; start_date.tm_year = 113;

  end_date.tm_hour = 0;  end_date.tm_min = 0;  end_date.tm_sec = 0;
  end_date.tm_mon = 3; end_date.tm_mday = 1; end_date.tm_year = 113;

  start_time = mktime(&start_date);
  end_time = mktime(&end_date);

  days = difftime(end_time, start_time) / 86400;

  printf ("%.f days difference\n", days);

  return 0;
}

Answer 1

Buddy只需尝试以下操作(将您的月份分别更改为1和2而不是2和3,它将为您提供正确的结果,此更改已经过测试).

根据Joachim和Floris的说法,对于tm_mon成员,Month为零,你计算的是3月1日到4月1日之间的差异,而不是2月1日和3月1日.

  start_date.tm_hour = 0;  start_date.tm_min = 0;  start_date.tm_sec = 0;
  start_date.tm_mon = 1; start_date.tm_mday = 1; start_date.tm_year = 112;

  end_date.tm_hour = 0;  end_date.tm_min = 0;  end_date.tm_sec = 0;
  end_date.tm_mon = 2; end_date.tm_mday = 1; end_date.tm_year = 112;