How to format date and time string in C++

c++ datetime mfc
Tae-Sung Shin picture Tae-Sung Shin · Apr 24, 2012 · Viewed 77.5k times · Source

Let's say I have time_t and tm structure. I can't use Boost but MFC. How can I make it a string like following?

Mon Apr 23 17:48:14 2012

Is using sprintf the only way?

Answer

Jerry Coffin picture Jerry Coffin · Apr 24, 2012

The C library includes strftime specifically for formatting dates/times. The format you're asking for seems to correspond to something like this:

char buffer[256];

strftime(buffer, sizeof(buffer), "%a %b %d %H:%M:%S %Y", &your_tm);

I believe std::put_time uses a similar format string, though it does relieve you of having to explicitly deal with a buffer. If you want to write the output to a stream, it's quite convenient, but to get it into a string it's not a lot of help -- you'd have to do something like:

std::stringstream buffer;

buffer << std::put_time(&your_tm, "%a %b %d %H:%M:%S %Y");

// now the result is in `buffer.str()`.

std::put_time is new with C++11, but C++03 has a time_put facet in a locale that can do the same thing. If memory serves, I did manage to make it work once, but after that decided it wasn't worth the trouble, and I haven't done it since.

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