C++ function to return current date (with zeros in month and day)

Question

I have this C++ function:

string date()
{
  time_t seconds = time (NULL);

struct tm * timeinfo = localtime (&seconds);

ostringstream oss;
oss << (timeinfo->tm_year + 1900) << "-" << (timeinfo->tm_mon + 1) << "-" << timeinfo->tm_mday; 
string data = oss.str();

return data;
}

The problem is I wanted the month and day with 0's. It's returning '2013-6-1' instead of '2013-06-01'

I'm trying to get this right with some if's and else's but I'm not getting anywhere..

Could you please help me?

Sounds like you're looking for something like this: http://stackoverflow.com/questions/1714515/how-can-i-pad-an-int-with-leading-zeros-when-using-cout-operator — veritasetratio, Jun 01 '13 at 21:23

score 2 · Answer 1 · answered Jun 01 '13 at 21:22

2

You can use the two stream modifiers std::setw and std::setfill with appropriate settings, for instance you can change your code to read:

string date()
{
   time_t seconds = time (NULL);

   struct tm * timeinfo = localtime (&seconds);

   ostringstream oss;
   oss << (timeinfo->tm_year + 1900) << "-" << std::setw(2) << std::setfill('0') << (timeinfo->tm_mon + 1) << "-" << std::setw(2) << std::setfill('0') << timeinfo->tm_mday; 
   string data = oss.str();

   return data;
}

answered Jun 01 '13 at 21:22

Thomas Russell

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1

Remember to `#include ` to use these output modifiers – djf Jun 01 '13 at 21:32
That did it! Thank you very much to all! – João Lima Jun 01 '13 at 21:34

perreal · Answer 2 · 2013-06-01T21:47:18.523

0

You can also use std::put_time, though not implemented in gcc 4.7:

std::string date()
{
    time_t seconds = time (NULL);
    struct tm * timeinfo = localtime (&seconds);
    std::ostringstream oss;
    oss << std::put_time(&timeinfo, "%Y-%m-%d");
    // or: oss << std::put_time(&timeinfo, "%F");
    return oss.str();
}

edited Jun 01 '13 at 21:47

answered Jun 01 '13 at 21:30

perreal

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And in C++11 (which is required for `std::put_time` anyway), you can use `%F`. – chris Jun 01 '13 at 21:35

C++ function to return current date (with zeros in month and day)

2 Answers2