how to split date/time in c++?

Question

I would like to spit a date/time string (for example 1/08/1957/11:20:01, or any type of time format) into month, hour, second, minute. The problem is that firstly I don't know how to define a type of time that can be split.

Should I write:

time_t now=1081987112001 s; //it is not correct. why? what's the c++ time data format?
struct tm* tm = localtime(&now);

cout << "Today is "
     << tm->tm_mon+1 // month
     << "/" << tm->tm_mday // day
     << "/" << tm->tm_year + 1900 // year with century
     << " " << tm->tm_hour // hour
     << ":" << tm->tm_min // minute
     << ":" << tm->tm_sec; // second

But it's not correct. Can someone give me an example with a method that takes a time value given from the keyboard and splits it?

What are the types of data times formats that c++ can accept?

Do you really mean "data time", or "date & time"? – Lightness Races in Orbit May 25 '11 at 14:54 — Lightness Races in Orbit, May 25 '11 at 14:54
data&time. can you please help? – marryy May 25 '11 at 14:56 — marryy, May 25 '11 at 14:56
I'm pretty sure you mean "date", not "data". – Lightness Races in Orbit May 25 '11 at 14:57 — Lightness Races in Orbit, May 25 '11 at 14:57

score 3 · Answer 1 · answered May 25 '11 at 14:59

3

If you looking to take the time from a user-input (which is what it seems like you're wanting), and convert that into a valid struct tm, you can use strptime() found in time.h.

So for instance, if you had:

char user_input_time[] = "25 May 2011 10:15:45";

struct tm;
strptime(user_input_time, "%d %b %Y %H:%M:%S", &tm);

printf("year: %d; month: %d; day: %d;\n", tm.tm_year, tm.tm_mon, tm.tm_mday);

answered May 25 '11 at 14:59

Jason

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strptime() isn't in the standard library. See http://stackoverflow.com/questions/321849/strptime-equivalent-on-windows – Ian Goldby May 25 '11 at 15:04
No, unfortunately it's not ... it's a POSIX function. But thank you for the link to a more portable version of that function ... that should definitely be helpful. – Jason May 25 '11 at 18:11

score 1 · Answer 2 · answered May 25 '11 at 14:57

1

time_t is an integer number and counts the number of seconds elapsed since the UNIX epoch: 1st Jan 1970, 00:00:00. You definitively cannot write what you did to assign this value.

You have to use the functions localtime or gmtime to convert between a convenient time_t value and a struct tm that have the various info of day, month, hour, etc.

You can also use the strftime and strptime functions to convert between a character string and struct tm.

answered May 25 '11 at 14:57

Didier Trosset

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"BOT"?! That date is called the UNIX epoch. – Lightness Races in Orbit May 25 '11 at 14:58
I usually call it BOT, for Begining Of Time. OK, I'll change it. – Didier Trosset May 25 '11 at 14:59
It's hardly the beginning of time! – Lightness Races in Orbit May 25 '11 at 14:59
Beginning Of Times, I suppose. (Wait, do you mean stuff actually *happened* before the 70s ?) – phtrivier May 25 '11 at 15:00

score 0 · Answer 3 · answered May 25 '11 at 14:56

0

#include <cstdio>
#include <iostream>
#include <string>
...
{
  std::string date_time;
  std::getline(std::cin, date_time);
  sscanf(date_time.c_str(), "%d/%d/%d/%d:%d:%d", &month, &date, &year, &hour, &minute, &second);
}

answered May 25 '11 at 14:56

Robᵩ

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this is the only way that a person can send the data and time? what if he sends yyyy.month.day.hour? – marryy May 25 '11 at 14:58
:) so i guess there has to be something that can take any value as a data/time value if it's correct and after that it splits it into hours, seconds and so on,no? – marryy May 25 '11 at 15:01
in c# the method is System.DataTime, in obj c its NSDate .in c++> – marryy May 25 '11 at 15:01
This (or better, `strptime`) is one way to parse a date if you know or specify the input format. If you don't know the input format in advance, you need to use a 3rd-party library. Google "c++ parse date" to look for one. – Robᵩ May 25 '11 at 15:04

how to split date/time in c++?

3 Answers3