Forgive the simple question, but I've been at this for hours, with no success. Im trying to implement a function:
std::string make_date_string()
I am using Howard Hinnant's date lib, which allows me to do stuff like this:
cout << floor<days>(system_clock::now());
printing something like:
2017-07-09
I'm trying to figure out how I can get that output to go in a std::string so I can return it from my function, but Im getting nowhere.
I'm trying to figure out how I can get that output to go in a std::string so I can return it from my function, but Im getting nowhere.
In such case you can use a std::ostringstream:
std::ostringstream oss;
oss << floor<days>(system_clock::now());
std::string time = oss.str();
As a side note:
As it looks like your helper function
template<typename Fmt>
floor(std::chrono::timepoint);
is implemented as an iostream manipulator, it can be used with any std::ostream implementation.
The accepted answer is a good answer (which I've upvoted).
Here is an alternative formulation using the same library:
#include "date.h"
#include <string>
std::string
make_date_string()
{
return date::format("%F", std::chrono::system_clock::now());
}
which creates a std::string with the "2017-07-09" format. This particular formulation is nice in that you don't have to explicitly construct a std::ostringstream, and you can easily vary the format to whatever you like, for example:
return date::format("%m/%d/%Y", std::chrono::system_clock::now());
which now returns "07/09/2017".
