我有这个程序可以找到epochT秒的日期和月份。我将发布代码并解释发生的意外情况。我确定它与代码中的for循环有关，但我会更详细地解释。我也想与处理类似问题的人分享我的算法，但我需要它先工作哈哈。
#include <curses.h>
#include <sys/time.h>
#include <time.h>
#include "fmttime.h" // Include for formattime interface
#include <strstream>
#include <iostream>
#include <iomanip>
static int monthindex; // Lookup table index
static const int milli = 1000; // Constant value for ms conversion
static const int epochyear = 1970; // Epoch year 1970
static const int leapy = 4; // Number of years for a leapyear
using namespace std;
struct Monthpairs // Fields for month & day lookup table
{
const char* mon; // Months
int day; // Days
};
Monthpairs months[] = // Lookup table for months & days
{
{"Jan", 31},
{"Feb", 28},
{"Mar", 31},
{"Apr", 30},
{"May", 31},
{"Jun", 30},
{"Jul", 31},
{"Aug", 31},
{"Sep", 30},
{"Oct", 31},
{"Nov", 30},
{"Dec", 31},
};
// Structure which will contain the human readable local
// time values
struct ExpandedTime
{
int et_usec; // Number of Milliseconds local time
int et_sec; // Number of Seconds local time
int et_min; // Number of minutes local time
int et_hour; // Number of hours local time
int et_day; // Day of the month local time
int et_mon; // Month of the year local time
int et_year; // Our current year (2013 present)
};
// Function prototype for Expanded time function
ExpandedTime* localTime(struct timeval* tv, ExpandedTime* etime);
// Expanded time will take the Epoch time and convert into days,
// months years, hours, minutes etc and then store this back into
// the Expanded Structure
ExpandedTime* localTime(
struct timeval* tv, // Pointer to timeval struct
ExpandedTime* etime // '' '' to expandedtime strct
)
{
tzset(); // Corrects for timezone
int epochT = (tv->tv_sec) - timezone; // Epoch seconds with
int epochUT = tv->tv_usec; // epochtime microseconds
int edays; // Days since epochtime
int days4years = 1461; // Number of days in 4 years
int fouryears; // Number of 4 year periods
int remaindays; // Number of days leftover
int tempdays; // Holds value of remaindays
int monthtracker; // Number of TOTAL months passed
// since current 4 year period
int daysgoneby; // Number of days passed
// since current 4 year period
etime->et_usec = (epochUT/milli) % milli; // Find the milliseconds
etime->et_sec = epochT % 60;
epochT /= 60; // Turn into minutes
etime->et_min = epochT % 60;
epochT /= 60; // Turn into hours
if (localtime(&tv->tv_sec)->tm_isdst !=0)
etime->et_hour = (epochT % 24) + 1; // Hours with DST correction
else
etime->et_hour = (epochT % 24);
edays = tv->tv_sec / 86400; // Turn into days since epochT
fouryears = edays / days4years;
remaindays = edays % days4years; // Determines which 4 year perio
tempdays = remaindays;
for (monthindex = 0 ; tempdays > 0 ; monthindex++)
{
daysgoneby += months[monthindex].day; // Keeps track of days passed
tempdays -= months[monthindex].day;
if (monthindex >= 11) // Resets counter for 12 months
{
monthindex = 0;
}
++monthtracker;
}
etime->et_day = tempdays + months[monthindex].day;
// This will take the number of months passed in current 4 year period
// and add it to the epoch year of 1970 to find the current year
etime->et_year = (monthtracker / 12) + (fouryears * 4) + epochyear;
return etime;
}
// Formats epoch time passed from a main function to a
// human readable string
char* formatTime(
struct timeval* tv, // Pointer to timeval struct
char* buf, // Pointer to char buf
size_t len // size of buffer
)
{
struct ExpandedTime etime2; // Struct object declaration
// Array containing strings for the months
/* const char* month[] =
{NOT USED OLD CODE BUT LEFT IN JUST IN CASE
"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
"Aug", "Sep", "Oct", "Nov", "Dec"
};*/
if (len > 0) // Will only print to valid sized buffer
{
localTime(tv, &etime2);
ostrstream oss(buf, len);
// Prints the time and date into a human readable string and
// places it in the supplied buffer from plot.cc
oss << etime2.et_year << " " << months[monthindex].mon << " " <<
etime2.et_day << " " << setw(2) << etime2.et_hour << ":"
<< setfill('0') << setw(2) << etime2.et_min << ":" << setfill('0')
<< setw(2) << etime2.et_sec << ":" << setfill('0') << setw(3) <<
etime2.et_usec << ends;
}
else if (len <= 0)
{
cout << "Sorry the length of the buffer is too small cannot write" << en
}
return buf;
}
所以继续我遇到的错误。在for循环中，“tempdays”出现了一些非常大的负值，就像我的“monthtracker”变量一样。我不知道这是怎么发生的。我每次循环运行时都将monthtracker递增1，并且我在进入循环之前检查了Tempdays，它有一个值= remaindays，它是1202.所以不知何故，这个值变为负数，这可以预期，但是它的大小数字似乎没有意义..
我试图实现的逻辑是，我可以找到自大纪元1970年1月1日以来已过去多少4年。从那以后，我可以找到剩余的剩余天数，这些天数不适合4年。使用该值，我遍历我的查找表months []并减去每个月的天数，直到临时值为0或小于0.我然后添加回“monthindex”中的哪个月停止查找当前日期。然而，在for循环之后，月度跟踪和临时问题的上述问题让我头疼不已。哦，在forloop里面，我一旦点击11就重置了monthindex计数器，因为我的查询表中只有12个月（因为应该有lol）。
编辑代码已编辑为更正。