C++

Forum

 
Creating a timeline with timers and events

Pages: 12
Amiplus (168)
Hello everyone.

I would like to create a timeline, setting a starting time and setting some time of events that triggers at specific time.

Any hint on how to proceed?

Thank you
jonnin (11442)
struct timeline
{
sometimetype timestamp;
string description;
};

vector<timeline>;
...

whenever something happens, pushback "now" time and what it was?
At the end, just iterate over the vector and crank out a report/graphic/something for your timeline.

you can clearly add more stuff to the struct and make it more fancy, this is just the bare-bones idea.

Last edited on
Amiplus (168)
Sorry, maybe i haven't well exaplained my problem.

I would like to set the date and time for example starting from 1 January 2141 and init a timer from this point in time.

Then, i would like to save the date and restart the timer from the saved date.
jonnin (11442)
you want a simulated timer for any date or you want a future timer to start on a future date?

This sounds more complex, involving at least a file for persistence.
jonnin (11442)
I generally try to do the keep it simple approach. I wonder if your basic approach could just be a 64 bit seconds since 1970 type value, with a few tagalong items for whatever else you need (what it is, is it active, ... whatever).

Amiplus (168)
"you want a simulated timer for any date or you want a future timer to start on a future date?"

Thank you for the reply.

Assuming i want to simulate that we are in the future (such in some games) and i have to manage date and time in that future, create events and so on...

I start set a date 01/01/2140, the start the timer, updating secondws, hours and days....

When i quit the game i store the current date/time in a file, when i restart the game i restart from the saved date/time
JLBorges (13770)
Assuming that the range of simulated time that we want to deal with is within the range of what the library can handle (for some typical values, see: http://www.cplusplus.com/forum/general/218890/#msg1009313
note that the GNU library is somewhat limited - upto year 2261 or so),
we could store the current simulated time in a std::time_t. This is an arithmetic type; so writing it to a file and reading it back later is directly supported.

Something along these lines, perhaps:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
 
#include <iostream>
#include <ctime>
#include <string>

struct timer
{
    timer( std::time_t simulated_time )
        : last_update_time( std::time(nullptr) ), simulated_time(simulated_time) {}

    timer( int year, int month /* jan == 1 */, int day )
    {
        std::tm tm {} ;
        tm.tm_year = year - 1900 ;
        tm.tm_mon = month - 1 ;
        tm.tm_mday = day ;
        simulated_time = std::mktime( std::addressof(tm) ) ;
        if( simulated_time == -1 ) throw std::out_of_range( "time is out of range" ) ;
        last_update_time = std::time(nullptr) ;
    }

    // call to update the simulated time. or call periodically
    // from a background thread (with std::atomic<time_t> simulated_time)
    void update()
    {
        const auto now = std::time(nullptr) ;
        simulated_time += std::difftime( now, last_update_time ) ;
        last_update_time = now ;
    }

    std::time_t current_simulated_time() { update() ; return simulated_time ; }

    std::string current_simulated_time_str()
    {
        update() ;
        const auto ptm = std::localtime( std::addressof(simulated_time) ) ;

        if(ptm) // if the c library supports this value for std::tm
        {
            char buffer[1024] {} ;
            std::strftime( buffer, sizeof(buffer), "%A, %B %d %H:%M:%S %Y", ptm ) ;
            return buffer ;
        }

        else return "time beyond what the C library can handle gracefully\n" ;
    }

    std::time_t last_update_time ; // actual calendar time
    std::time_t simulated_time ; // simulated time at the time of last update

    // save the state of the timer (current simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, const timer& t )
    { return stm << t.simulated_time ; }

    // restore the state of the timer  (current simulated time) from an input stream
    friend std::istream& operator >> ( std::istream& stm, timer& t )
    {
        std::time_t stime ;
        if( stm >> stime ) t = { stime } ;
        return stm ;
    }
};


Simple example usage:
1
2
3
4
5
6
7
8
9
10
11
12
13
 
int main()
{
    timer t { 2056, 7, 12 } ;
    std::cout << t << '\n' ;

    for( int i = 0 ; i < 10 ; ++i )
    {
        std::cout << "press enter: " && std::cin.get() ;
        std::cout << "simulated time: " << t.current_simulated_time_str() << '\n' ;
    }

    std::cout << t << '\n' ;
}

Amiplus (168)
Thank you.

I managed to create something similar, but your code is better for sure.

I'll try study the code.

Is this "custom" time updatable by seconds, hours or days?

"std::out_of_range" is this part of std?


Btw the code works on simulator online, but doesn't work on my desktop. I get:

"main.cpp|2451|error: expected ';' before 't';|
Last edited on
JLBorges (13770)
> Is this "custom" time updatable by seconds, hours or days?

As written, the functions timer::current_simulated_time() and timer::current_simulated_time_str() would return the current updated time; that is the reason why they are not const-qualified.

As long as we use one of these functions to retrieve the current simulated time we would get the most up to date time, accurate to within a second or so.

I had missed updating the time in the stream insertion operator; ideally it should have an overload:
1
2
3
4
5
6
7
 
    // save the state of the timer (current simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, const timer& t ) // const timer
    { return stm << t.simulated_time ; }

    // save the state of the timer (updated current simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, timer& t ) // non-const timer; update and save the up to date state
    { return stm << t.current_simulated_time() ; }



> "std::out_of_range" is this part of std?

Yes. http://en.cppreference.com/w/cpp/error/out_of_range
Last edited on
Amiplus (168)
Thank you.

Can't set the date years 2140. Always remain to 1970.

about the new function: should substitute the other function in the previous code?

Moreover, could be possible to autoupdate the time each second?

What if i want to update at certain point the date jumping forward by 7 days?

Last edited on
Amiplus (168)
Always out of range, don't understand why
JLBorges (13770)
> "main.cpp|2451|error: expected ';' before 't';|

Please tell me that the 2451 is not the line number; surely you can't be having a main.cpp with 2451+ lines.


> about the new function: should substitute the other function in the previous code?

You can just add the new function (it would become an overloaded overloaded operator).


> Can't set the date years 2140. Always remain to 1970.

It would help if you specify which compiler/library is being used (include the version).
All the mainstream implementations can handle years up to 2900 AD.

Linux, clang++ / libc++ : at least up to 3200 AD
Linux, g++ / libstdc++ : at least up to 3200 AD
http://coliru.stacked-crooked.com/a/1f2971a1ec691de5

Microsoft, GNU/MinGW : up to 2900 AD or so
http://rextester.com/VRRH57759


> What if i want to update at certain point the date jumping forward by 7 days?

See the highlighted portion of the code:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
 
#include <iostream>
#include <ctime>
#include <string>

struct timer
{
    timer( std::time_t simulated_time )
        : last_update_time( std::time(nullptr) ), simulated_time(simulated_time) {}

    timer( int year, int month /* jan == 1 */, int day )
    {
        std::tm tm {} ;
        tm.tm_year = year - 1900 ;
        tm.tm_mon = month - 1 ;
        tm.tm_mday = day ;
        simulated_time = std::mktime( std::addressof(tm) ) ;
        if( simulated_time == -1 ) throw std::out_of_range( "time is out of range" ) ;
        last_update_time = std::time(nullptr) ;
    }

    static double ticks_per_sec() // just to be pedanticaly safe: almost always is 1 tick per second
    {
        static const int NTICKS = 10000 ;
        static const double ticks_per_second = NTICKS / std::difftime( std::time_t(NTICKS*2), std::time_t(NTICKS) ) ;
        return ticks_per_second ;
    }

    // call to update the simulated time. or call periodically
    // from a background thread (with std::atomic<time_t> simulated_time)
    void update()
    {
        const auto now = std::time(nullptr) ;

        // add the elapsed time between now and last updated time
        simulated_time += ticks_per_sec() * std::difftime( now, last_update_time ) ;

        last_update_time = now ; // and set the last updated time to now
    }

    void advance_secs( int secs )
    {
        update() ;
        simulated_time += secs * ticks_per_sec() ;
    }

    void advance_minutes( int minutes ) { advance_secs( minutes * 60 ) ; }
    void advance_hours( int hrs ) { advance_minutes( hrs * 60 ) ; }
    void advance_days( int days ) { advance_hours( days * 24 ) ; }

    void advance_months( int months )
    {
        update() ;
        std::tm tm = *std::localtime( std::addressof(simulated_time) ) ;
        tm.tm_mon += months ;

        simulated_time = std::mktime( std::addressof(tm) ) ;
        if( simulated_time == -1 ) throw std::out_of_range( "time is out of range" ) ;

        last_update_time = std::time(nullptr) ;
    }

    void advance_years( int yrs ) { advance_months( yrs * 12 ) ; }

    std::time_t current_simulated_time() { update() ; return simulated_time ; }

    std::string current_simulated_time_str()
    {
        update() ;
        const auto ptm = std::localtime( std::addressof(simulated_time) ) ;

        if(ptm) // if the c library supports handling this value for std::tm
        {
            char buffer[1024] {} ;
            std::strftime( buffer, sizeof(buffer), "%A, %B %d %H:%M:%S %Y", ptm ) ;
            return buffer ;
        }

        else return "time beyond what the C library can handle gracefully\n" ;
    }

    private:
        std::time_t last_update_time ; // actual calendar time
        std::time_t simulated_time ; // simulated time at the time of last update

    // save the state of the timer (current simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, const timer& t )
    { return stm << t.simulated_time ; }

    // save the state of the updated timer (updated simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, timer& t )
    { return stm << t.current_simulated_time() ; }

    // restore the state of the timer  (current simulated time) from an input stream
    friend std::istream& operator >> ( std::istream& stm, timer& t )
    {
        std::time_t stime ;
        if( stm >> stime ) t = { stime } ;
        return stm ;
    }
};



> Moreover, could be possible to autoupdate the time each second?

Possible (with a background thread).
But what would be the use-case for doing something like that?
Amiplus (168)
Thank you for the reply.

Main have few lines.

The compiler is GNU. I'm using minGW under Windows. GCC version is 4.9.2
JLBorges (13770)
> Main have few lines.

2451 is not 'a few lines'. Factor it out into separate, manageable components.

> The compiler is GNU. I'm using minGW under Windows. GCC version is 4.9.2

I do not have access to that version.

I've tested with the versions I have immediate access to, and this is what I get:

Nuwen: https://nuwen.net/mingw.html
MinGW version: 5.0
GNU compiler version: 7.1.0
-----------------------------------------------
    initial: Monday, October 17 00:00:00 2140
   +73 secs: Monday, October 17 00:01:13 2140
   -88 mins: Sunday, October 16 22:33:13 2140
  -423 days: Thursday, August 20 22:33:13 2139
-142 months: Monday, October 20 22:33:13 2127
  +75 years: Wednesday, October 20 22:33:13 2202
 +100 years: Monday, October 20 22:33:13 2302
 +100 years: Sunday, October 20 22:33:13 2402
 +100 years: Friday, October 20 22:33:13 2502
 +100 years: Wednesday, October 20 22:33:13 2602
 +100 years: Monday, October 20 22:33:13 2702
 +100 years: Sunday, October 20 22:33:13 2802
 +100 years: Friday, October 20 22:33:13 2902
 +100 years: *** error: time is out of range


TDM-GCC-64 http://tdm-gcc.tdragon.net/index.php/
MinGW version: 4.0
GNU compiler version: 5.1.0
-----------------------------------------------
    initial: Monday, October 17 00:00:00 2140
   +73 secs: Monday, October 17 00:01:13 2140
   -88 mins: Sunday, October 16 22:33:13 2140
  -423 days: Thursday, August 20 22:33:13 2139
-142 months: Monday, October 20 22:33:13 2127
  +75 years: Wednesday, October 20 22:33:13 2202
 +100 years: Monday, October 20 22:33:13 2302
 +100 years: Sunday, October 20 22:33:13 2402
 +100 years: Friday, October 20 22:33:13 2502
 +100 years: Wednesday, October 20 22:33:13 2602
 +100 years: Monday, October 20 22:33:13 2702
 +100 years: Sunday, October 20 22:33:13 2802
 +100 years: Friday, October 20 22:33:13 2902
 +100 years: *** error: time is out of range


The code is almost identical to this http://coliru.stacked-crooked.com/a/1f2971a1ec691de5

This is how it could be factored into separate components:

Header timer.h 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
 
#ifndef TIMER_H_INCLUDED
#define TIMER_H_INCLUDED

#include <ctime>
#include <string>
#include <iostream>

struct timer
{
    timer( std::time_t simulated_time )
        : last_update_time( std::time(nullptr) ), simulated_time(simulated_time) {}

    timer( int year, int month /* jan == 1 */, int day ) ;

    static double ticks_per_sec() ; // just to be pedanticaly safe: almost always is 1 tick per second

    // call to update the simulated time. or call periodically
    // from a background thread (with std::atomic<time_t> simulated_time)
    void update() ;

    void advance_secs( int secs )
    {
        update() ;
        simulated_time += secs * ticks_per_sec() ;
    }

    void advance_minutes( int minutes ) { advance_secs( minutes * 60 ) ; }
    void advance_hours( int hrs ) { advance_minutes( hrs * 60 ) ; }
    void advance_days( int days ) { advance_hours( days * 24 ) ; }

    void advance_months( int months ) ;
    void advance_years( int yrs ) { advance_months( yrs * 12 ) ; }

    std::time_t current_simulated_time() { update() ; return simulated_time ; }

    std::string current_simulated_time_str() ;

    private:
        std::time_t last_update_time ; // actual calendar time
        std::time_t simulated_time ; // simulated time at the time of last update

    // save the state of the timer (current simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, const timer& t )
    { return stm << t.simulated_time ; }

    // save the state of the updated timer (updated simulated time) into an output stream
    friend std::ostream& operator << ( std::ostream& stm, timer& t )
    { return stm << t.current_simulated_time() ; }

    // restore the state of the timer  (current simulated time) from an input stream
    friend std::istream& operator >> ( std::istream& stm, timer& t )
    {
        std::time_t stime ;
        if( stm >> stime ) t = { stime } ;
        return stm ;
    }
};

#endif // TIMER_H_INCLUDED


Implementation timer.cpp 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
 
#include "timer.h"

timer::timer( int year, int month /* jan == 1 */, int day )
{
    std::tm tm {} ;
    tm.tm_year = year - 1900 ;
    tm.tm_mon = month - 1 ;
    tm.tm_mday = day ;
    simulated_time = std::mktime( std::addressof(tm) ) ;
    if( simulated_time == -1 ) throw std::out_of_range( "time is out of range" ) ;
    last_update_time = std::time(nullptr) ;
}

double timer::ticks_per_sec()
{
    static const int NTICKS = 10000 ;
    static const double ticks_per_second = NTICKS / std::difftime( std::time_t(NTICKS*2), std::time_t(NTICKS) ) ;
    return ticks_per_second ;
}

void timer::update()
{
    const auto now = std::time(nullptr) ;

    // add the elapsed time between now and last updated time
    simulated_time += ticks_per_sec() * std::difftime( now, last_update_time ) ;

    last_update_time = now ; // and set the last updated time to now
}

void timer::advance_months( int months )
{
    update() ;
    std::tm tm = *std::localtime( std::addressof(simulated_time) ) ;
    tm.tm_mon += months ;

    simulated_time = std::mktime( std::addressof(tm) ) ;
    if( simulated_time == -1 ) throw std::out_of_range( "time is out of range" ) ;

    last_update_time = std::time(nullptr) ;
}

std::string timer::current_simulated_time_str()
{
    update() ;
    const auto ptm = std::localtime( std::addressof(simulated_time) ) ;

    if(ptm) // if the c library supports handling this value for std::tm
    {
        char buffer[1024] {} ;
        std::strftime( buffer, sizeof(buffer), "%A, %B %d %H:%M:%S %Y", ptm ) ;
        return buffer ;
    }

    else return "time beyond what the C library can handle gracefully\n" ;
}


Test frame main.cpp 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
 
#include <iostream>
#include "timer.h"

int main()
{
    #ifdef __MINGW64__
        std::cout << "MinGW version: " << __MINGW64_VERSION_STR << '\n'
                  << "GNU compiler version: " << __VERSION__
                  << "\n-----------------------------------------------\n" ;

    #endif // __MINGW64__

    timer t( 2140, 10, 17 ) ;
    std::cout << "    initial: " << t.current_simulated_time_str() << '\n' ;

    t.advance_secs(73) ; // forward by 73 seconds
    std::cout << "   +73 secs: " << t.current_simulated_time_str() << '\n' ;

    t.advance_minutes( -88 ) ; // back by 88 minutes
    std::cout << "   -88 mins: " << t.current_simulated_time_str() << '\n' ;

    t.advance_days(-423) ; // back by 423 days
    std::cout << "  -423 days: " << t.current_simulated_time_str() << '\n' ;

    t.advance_months(-142) ; // back by 142 months
    std::cout << "-142 months: " << t.current_simulated_time_str() << '\n' ;

    t.advance_years(75) ; // forward by 75 years
    std::cout << "  +75 years: "<< t.current_simulated_time_str() << '\n' ;

    try
    {
        for( int i = 0 ; i < 10 ; ++i )
        {

            std::cout << " +100 years: " ;
            t.advance_years(100) ; // forward by 100 years
            std::cout << t.current_simulated_time_str() << '\n' ;
        }
    }
    catch( const std::exception& e )
    {
        std::cerr << "*** error: " << e.what() << '\n' ;
    }
}


Try this code out on the implementation that you have; I would expect that the results would be similar (handle times up to 2900 AD or so).

It would be a good idea to move to a more current version of the compiler; the versions I tested with can be downloaded from the links indicated earlier.
Amiplus (168)
Sorry for the late reply.

Thank you for your very detailed explaination and code factorization: very useful and informative.

I will try as soon as possible the code.

Kind regards
Amiplus (168)
@JLBorges

Hello,

tried the code above.
Still have problem with "throw std::out_of_range( "time is out of range" ) ;" the error say that out_of_range is not part of std.

Btw, replacing the "throw std::out_of_range( "time is out of range" ) ;" with a simple cout ... the software works with the following output:

"time is out of range
initial: time beyond what the C library can handle gracefully"

then continue to works till

1
2
 
t.advance_days(-423) ; // back by 423 days
    std::cout << "  -423 days: " << t.current_simulated_time_str() << '\n' ;


if i use the

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
    t.advance_months(-142) ; // back by 142 months
    std::cout << "-142 months: " << t.current_simulated_time_str() << '\n' ;

    t.advance_years(75) ; // forward by 75 years
    std::cout << "  +75 years: "<< t.current_simulated_time_str() << '\n' ;

    try
    {
        for( int i = 0 ; i < 10 ; ++i )
        {

            std::cout << " +100 years: " ;
            t.advance_years(100) ; // forward by 100 years
            std::cout << t.current_simulated_time_str() << '\n' ;
        }
    }
    catch( const std::exception& e )
    {
        std::cerr << "*** error: " << e.what() << '\n' ;
    }


the software crash

I'm wondering if my codeblocks + mingw setup works.
Last edited on
JLBorges (13770)
> Still have problem with "throw std::out_of_range( "time is out of range" ) ;"
> the error say that out_of_range is not part of std.

Mea culpa; in timer.cpp, we need to add #include <stdexcept>
http://en.cppreference.com/w/cpp/error/out_of_range



> I'm wondering if my codeblocks + mingw setup works.

The results I get with the two versions of MinGW that I have was posted here:
http://www.cplusplus.com/forum/beginner/219322/#msg1011039

If an older version (versions prior to GCC 5.1) of the GNU compiler library is still being used, you should upgrade immediately; older versions of the GNU library would be thoroughly broken in many places.
Amiplus (168)
@JLBorges

Can't find a suitable (ready made) MINGW installation to replace the MINGW directory of codeblocks.
JLBorges (13770)
Amiplus (168)
Thank you.

I used this website in the past, but I completely forgot it. Very useful
Pages: 12