How Can C 11 Parse Historical Date Strings and Calculate Elapsed Time?

Parsing Historical Date Strings with C 11

Consider a date string in the format "Thu Jan 9 12:35:34 2014." The goal is to convert this string into a C date representation and determine the elapsed time from that date. To achieve this, we can leverage the features of the C 11 standard library.

Using the std::chrono namespace, we can obtain a time point from a std::tm struct. The std::tm struct stores date and time information, while the std::chrono namespace provides time manipulation capabilities.

To parse the date string, we can use the std::get_time function, which is available in C 11 onwards. For older GCC versions (prior to 5), we can alternatively use the strptime function. Both functions populate a std::tm struct with the parsed date information.

Once we have the std::tm struct, we can utilize the std::chrono::system_clock::from_time_t function to convert the time represented by the struct into a std::chrono::time_point. This time_point represents a point in time on the system clock.

Using this time_point, we can calculate the elapsed time from the parsed date to the current time. The std::chrono library provides various methods for time manipulation, allowing us to extract the required information like seconds, minutes, hours, and days from the duration.

In summary, leveraging the std::chrono namespace and the std::tm struct, we can effectively parse historical date strings and determine the elapsed time from those dates with precision.

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