Finding the difference between dates with std::chrono

20 Oct 2023

datetime

Working with dates and time durations is a common task in many software applications. In C++, the <chrono> library provides functionality for dealing with dates, durations, and time points. One common task is finding the difference between two dates using std::chrono.

To calculate the difference between two dates, we can use the std::chrono::duration class. Here’s an example of how to do it:

#include <iostream>
#include <chrono>

int main() {
  // Create date points
  std::chrono::system_clock::time_point start = std::chrono::system_clock::now();
  std::chrono::system_clock::time_point end = std::chrono::system_clock::now() - std::chrono::hours(24);

  // Calculate the difference
  std::chrono::duration<double> difference = end - start;

  // Print the difference
  std::cout << "The difference between the two dates is: " << difference.count() << " seconds" << std::endl;

  return 0;
}

In this example, the std::chrono::system_clock::now() function is used to get the current date and time as time_point objects. We then create start and end dates for the purposes of demonstration.

To calculate the difference between two dates, we simply subtract the earlier date from the later date. The result is a duration object representing the time difference between the two dates.

Finally, we can print the difference using the count() member function of the duration object. In this example, the difference is printed in seconds, but you can easily convert it to other time units, such as minutes, hours, or days.

Remember to include the necessary headers <iostream> and <chrono>, and to use the std:: prefix before the relevant classes and functions.

Using std::chrono makes it easy to perform date and time calculations in C++. It provides a flexible and portable way to work with dates and durations. Whether you need to calculate time differences, measure elapsed time, or perform other date-related calculations, std::chrono has got you covered.

References:

#cpp #datetime