C编程中的日期比较 [英] Date Comparision in C programming

问题描述

嗨
我需要在纯C语言中进行日期比较.
一个是char Date_1 [8]，另一个是#defined常量"DATE2"
我想使用上述2个日期中的最新日期，并将其存储到文件中.

有人可以帮我吗?

提前致谢. :-O

Hi
I need to do the date comparision in plain C.
one is the char Date_1[8] and other is #defined constant "DATE2"
I want to use most recent date from above 2 dates and store it into a file.

Can anybody help me out.

Thanks in advance. :-O

推荐答案

如果允许
将日期编码为"YYYYMMDD"，

您可以使用:):

If it is allowed
to code the date as "YYYYMMDD",

you could use :) :

#define d2 "19001229"
...
{
...
  char d1[8] = {''2'',''0'',''1'',''0'',''0'',''4'',''0'',''6''};
  int iResult = memcmp(d1 /*address of date1*/,
                       d2 /*address of date2*/,
                       sizeof(d1) /*=8, length to compare*/);
}

感谢回复.

但是我的日期格式是dd/mm/yyyy
我如何比较它们?
比较年，月，日.
我想使用最近的日期. :-O

Thanks for reply.

But my date format is dd/mm/yyyy
How can i compare them?
compare year, month ,date.
I want to use the most recent date. :-O

保存和比较日期的另一种方法:):

Another solution to hold and compare the dates :) :

typedef struct sMydate {
  WORD m_wYear;
  BYTE m_byMonth;
  BYTE m_byDay;
 

  sMydate(WORD wYear, BYTE byMonth, BYTE byDay) {
    m_wYear   = wYear;
    m_byMonth = byMonth;
    m_byDay   = byDay;
  }
 

  int Compare(const sMydate& sAnotherDate) {
    LONG lThisDate = MAKELONG(MAKEWORD(m_byDay, m_byMonth), m_wYear);
    LONG lAnotherDate = MAKELONG(MAKEWORD(sAnotherDate.m_byDay,
                                          sAnotherDate.m_byMonth),
                                 sAnotherDate.m_wYear);
 

    return memcmp(&lThisDate, &lAnotherDate, sizeof(LONG));
  }
} MYDATE, *LPMYDATE;
...
const MYDATE sConstDate(1900, 12, 29);
...
{
...
  MYDATE sLocalDate(2010, 04, 06);
  int iResult = sLocalDate.Compare(sConstDate);
...
}

;

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