This project provides a source code for my talk at EPAM's Zed 2020 conference.

During the talk I compare safety, user experience, and performance of a similar scenario in 3 different programming languages: Java, Python, and C++. The discussed feature is the physical units library.

• Java: JSR 385 - Units of Measurement
• Python: Pint
• C++: mp-units

1. Functional

   • implement avg_speed function that takes length and time arguments and returns speed in the unit derived from the units of function arguments
   • calculate avg_speed(220 km, 2 h) and print the result in km/h and m/s
   • calculate avg_speed(140 mi, 2 h) and print the result in mi/h and m/s

2. Safety

   • ensure that for reordered arguments avg_speed(2 h, 220 km) returns an error
   • ensure that an error is reported when avg_speed returns the result of an invalid calculation
     • function multiplies the arguments instead of dividing them
     • the result is not a quantity of speed

3. Efficiency

   • benchmark the following scenarios both for operations on fundamental/primitive types and on high-level abstractions
     • create the quantities of length and time and divide them to obtain speed
     • create a quantity of speed and convert the unit from km/h to m/s
   • check how much more memory is needed for a high-level abstraction (quantity class) compared to the fundamental/primitive magnitude type