diff --git a/Examples-and-Recipes.md b/Examples-and-Recipes.md index af5137f..a5c182d 100644 --- a/Examples-and-Recipes.md +++ b/Examples-and-Recipes.md @@ -1,6 +1,8 @@ This page contains examples and recipes contributed by community members. Feel free to add your own contributions by clicking on the "Edit" button. Please "sign" your contributions by adding a link to your GitHub profile. **But please understand that your contributions will henceforth be considered donated under the [Creative Commons Attribution 4.0 International License](http://creativecommons.org/licenses/by/4.0/)**. If this requirement is a problem for anyone, bring it to Howard's attention and we will try to work out a compromise. ##Contents +- [The current local time](#localtime) +- [The current time somewhere else](#elsetime) - [Obtaining a `time_point` from `y/m/d h:m:s` components](#time_point_to_components) - [Obtaining `y/m/d h:m:s` components from a `time_point`](#components_to_time_point) - [Normalizing `y/m/d` when it is `!ok()`](#normalize) @@ -19,6 +21,56 @@ This page contains examples and recipes contributed by community members. Feel f *** + +### The current local time +(by [Howard Hinnant](https://github.com/HowardHinnant)) + +This couldn't be easier: + +```c++ +#include "tz.h" +#include + +int +main() +{ + std::cout << date::make_zoned(date::current_zone(), std::chrono::system_clock::now()) << '\n'; +} +``` + +`system_clock::now()` of course gets the current time. It is a de facto standard that this current time is measured in terms of [Unix Time](https://en.wikipedia.org/wiki/Unix_time) which is a very close approximation to UTC. `make_zoned` pairs the current UTC time with the computer's current local time zone, producing a `zoned_time`. The `zoned_time` has a streaming operator so you can easily print it out: + +```c++ +2016-07-05 23:01:05.818378 EDT +``` + +Note that the precision of this output is with whatever precision your `system_clock::now()` supports (microseconds on macOS where I'm writing this). + + +### The current time somewhere else +(by [Howard Hinnant](https://github.com/HowardHinnant)) + +If you need to find out the current time where you _aren't_, then that is a simple matter too: + +```c++ +#include "tz.h" +#include + +int +main() +{ + std::cout << date::make_zoned("Asia/Shanghai", std::chrono::system_clock::now()) << '\n'; +} +``` + +This outputs the current time in Shanghai, for example: + +```c++ +2016-07-06 11:01:05.818378 CST +``` + +All IANA timezone names (or links -- aliases to timezones) are supported. + ### Obtaining a `time_point` from `y/m/d h:m:s` components (by [ecorm](https://github.com/ecorm))