Convert string datetime in C++

Question

I have a date represented as string in the format "2012-10-28" and I want to convert it in the string format of "28/10/2012". Is this possible in C++ MS Visual Studio using a predefined function ?

are you talking about replacing all "-" to "/" in your string or you need some Time function to do that? — Abhineet, Mar 06 '13 at 13:25

score 3 · Answer 1 · answered Mar 06 '13 at 15:26

This will do it:

#include <cstdio>
#include <iostream>
#include <string>
using namespace std;

string format_date(string s)
{
    char buf[11];
    int a, b, c;
    sscanf(s.c_str(), "%d-%d-%d", &a, &b, &c);
    sprintf(buf, "%02d/%02d/%d", c, b, a);
    return buf;
}

int main()
{
    cout << format_date("2012-09-28") << endl;
}

score 2 · Accepted Answer · answered Mar 06 '13 at 13:44

2

I worked it out that way:

 Use sscan_f to break date into year, month and day.
 Create struct tm with the data above.
 Use strftime to convert from tm to string with the desired format.

answered Mar 06 '13 at 13:44

user1845360

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score 1 · Answer 3 · answered Mar 06 '13 at 13:10

1

Please look at COleDateTime::ParseDateTime.

If do not want to use COleDateTime the implementation of the ParseDateTime is just a thin wrapper around VarDateFromStr.

answered Mar 06 '13 at 13:10

Lucian

3,407
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score 0 · Answer 4 · edited May 23 '17 at 12:27

0

strptime unfortunately does not exist in windows. Seek help here: strptime() equivalent on Windows?

You can then write the date using strftime.

edited May 23 '17 at 12:27

Community

1
1

answered Mar 06 '13 at 12:59

Dariusz

21,561
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score 0 · Answer 5 · answered Dec 11 '13 at 19:24

in Qt (some embedded system does not support new timer class yet, so here) I here just give the idea how to convert a string without much mumbo jumbo. the timer class has the epoch function anyway.

QString fromSecsSinceEpoch(qint64 epoch)
{
    QTextStream ts;
    time_t result = epoch;//std::time(NULL);
    //std::cout << std::asctime(std::localtime(&result))
    //            << result << " seconds since the Epoch\n";
    ts << asctime(gmtime(&result));
    return ts.readAll();
}
qint64 toSecsSinceEpoch(QString sDate)//Mon Nov 25 00:45:23 2013
{
    QHash <QString,int> monthNames;
    monthNames.insert("Jan",0);
    monthNames.insert("Feb",1);
    monthNames.insert("Mar",2);
    monthNames.insert("Apr",3);
    monthNames.insert("May",4);
    monthNames.insert("Jun",5);
    monthNames.insert("Jul",6);
    monthNames.insert("Aug",7);
    monthNames.insert("Sep",8);
    monthNames.insert("Oct",9);
    monthNames.insert("Nov",10);
    monthNames.insert("Dec",11);


    QStringList l_date = sDate.split(" ");
    if (l_date.count() != 5)
    {
        return 0;//has to be 5 cuz Mon Nov 25 00:45:23 2013
    }
    QStringList l_time = l_date[3].split(":");
    if (l_time.count() != 3)
    {
        return 0;//has to be 3 cuz 00:45:23
    }

    struct tm result;
    result.tm_mday=l_date[2].toInt();
    result.tm_mon=monthNames[l_date[1]];
    result.tm_year=l_date[4].toInt()-1900;;

    result.tm_hour=l_time[0].toInt();
    result.tm_min=l_time[1].toInt();
    result.tm_sec=l_time[2].toInt();
    time_t timeEpoch=mktime(&result);
    qDebug()<<"epochhhh :"<<timeEpoch;
    return timeEpoch;
}

Convert string datetime in C++

5 Answers5