Solutions

Here are the solutions for the above problem-solving sections.

39. Measuring function execution time

To measure the execution time of a function, you should retrieve the current time before the function execution, execute the function, then retrieve the current time again and determine how much time passed between the two time points. For convenience, this can all be put in a variadic function template that takes as arguments the function to execute and its arguments, and:

• Uses std::high_resolution_clock by default to determine the current time.
• Uses std::invoke() to execute the function to measure, with its specified arguments.
• Returns a duration and not a number of ticks for a particular duration. This is important so that you don't lose resolution. It enables you to add execution time duration of various resolutions, such as seconds and milliseconds, which would not be possible by returning a tick count:

template <typename Time = std::chrono::microseconds,
          typename Clock...