判断两个时间是同一天

bool IsToday(time_t nLastTime, time_t nNowTime)
{
 time_t LastTime = nLastTime;
 struct tm localTime;
 localtime_r(&LastTime, &localTime);

 time_t NowTime = nNowTime;
 struct tm localNowTime;
 localtime_r(&NowTime, &localNowTime);

 if (localTime.tm_year == localNowTime.tm_year &&
   localTime.tm_mon == localNowTime.tm_mon &&
   localTime.tm_mday == localNowTime.tm_mday)
 {
  return true;
 }
 else
  return false;
}

扩展

bool CTimer::IsToday() const
{
 if (m_Time == 0)
  return false;
 time_t NowTime = time(NULL);
    struct tm localNowTime;
    localtime_r(&NowTime, &localNowTime);

 struct tm localTime;
    localtime_r(&m_Time, &localTime);

 if (localTime.tm_year == localNowTime.tm_year &&
   localTime.tm_mon == localNowTime.tm_mon &&
   localTime.tm_mday == localNowTime.tm_mday)
 {
  return true;
 }
 else
  return false;
}

bool CTimer::IsThisWeek() const
{
 if (m_Time == 0)
  return false;
 time_t NowTime = time(NULL);
 struct tm localNowTime;
 localtime_r(&NowTime, &localNowTime);

 struct tm localTime;
 localtime_r(&m_Time, &localTime);

 return (localTime.tm_year == localNowTime.tm_year &&
 (localTime.tm_yday - localNowTime.tm_yday) == (GetWeek7Day(m_Time) - GetWeek7Day(NowTime)));
}

int CTimer::GetWeek7Day(time_t tTime) const
{
 struct tm localNowTime;
 localtime_r(&tTime, &localNowTime);
 return localNowTime.tm_wday == 0 ? 7 : localNowTime.tm_wday;
}

bool CTimer::IsThisMonth() const
{
 if (m_Time == 0)
  return false;
 time_t NowTime = time(NULL);
 struct tm localNowTime;
 localtime_r(&NowTime, &localNowTime);

 struct tm localTime;
 localtime_r(&m_Time, &localTime);

 return (localTime.tm_year == localNowTime.tm_year &&
   localTime.tm_mon == localNowTime.tm_mon);
}

bool CTimer::IsYesterday() const
{
    time_t NowTime = time(NULL);
    struct tm local;
    localtime_r(&NowTime, &local);
    struct tm LoaclTime;
    localtime_r(&m_Time, &LoaclTime);
    if (LoaclTime.tm_year != local.tm_year)
        return false;

    return (local.tm_yday - LoaclTime.tm_yday) == 1;
}

time_t CTimer::GetSunday() const
{
 time_t NowTime = time(NULL);
 struct tm local;
 localtime_r(&NowTime, &local);
 local.tm_mday = local.tm_mday - local.tm_wday + 1; //加1表示星期一的零时
 local.tm_hour = 0;
 local.tm_min = 0;
 local.tm_sec = 0;
 time_t Sunday = mktime(&local);
 return Sunday;
}

int CTimer::GetYear() const
{
 struct tm localNowTime;
 localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_year + 1900;
}
int CTimer::GetMonth() const
{
 struct tm localNowTime;
 localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_mon + 1;
}
int CTimer::GetDay() const
{
 struct tm localNowTime;
 localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_mday;
}
int CTimer::GetHour() const
{
 struct tm localNowTime;
 localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_hour;
}
int CTimer::GetMinute() const
{
    struct tm localNowTime;
    localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_min;
}
int CTimer::GetSecond() const
{
    struct tm localNowTime;
    localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_sec;
}
int CTimer::GetYearDay() const
{
    struct tm localNowTime;
    localtime_r(&m_Time, &localNowTime);
    return localNowTime.tm_yday;
}

int CTimer::Get12Clock() const
{
 struct tm localNowTime;
 localtime_r(&m_Time, &localNowTime);
 localNowTime.tm_mday = localNowTime.tm_mday + 1;
 localNowTime.tm_hour = 0;
 localNowTime.tm_min = 0;
 localNowTime.tm_sec = 0;
 time_t tToNight = mktime(&localNowTime);
 return tToNight - m_Time;
}
time_t CTimer::GetDate() const
{
  struct tm localNowTime;
  localtime_r(&m_Time, &localNowTime);
 localNowTime.tm_hour = 0;
 localNowTime.tm_min = 0;
 localNowTime.tm_sec = 0;
 time_t date = mktime(&localNowTime);
 return date;
}
int CTimer::GetWeekDay() const
{
    struct tm localNowTime;
    localtime_r(&m_Time, &localNowTime);
 return localNowTime.tm_wday;
}