This project was developed by Prateek Sahay for nuTonomy's coding exercise.

The calculation engine's purpose is to perform generic calculations on a set of integers. It can run on a list of integers passed as command line arguments or by reading integers from a file. IntStreamer, built into the library for parsing these integers, will read up to the end of the file or until it encounters a broken integer (characters instead of numbers, integers larger than 32 bits, etc.).

• gcc in the instructions refers to the collection of GNU compilers (which includes g++), not the C compiler.
• If the user passes 3 arguments, e.g. ./calc_example <engine_name> <arg2> then arg2 refers to a file (rather than a list of 1 integer).
• Skipping unit tests for the IntStreamer class because of the instructions, but in reality it seems crucial to test on empty files, corrupt file data, etc.
• I've chosen to take "integers" in the instructions to mean 32-bit signed integers.
• Engines can return floating point results.

• GTest: sudo dnf install gtest-devel
• Doxygen: sudo dnf install doxygen

Building:

mkdir build
cd build
cmake ..
make

# Optionally build Doxygen docs
make doc

Running:

# Run GTests
./bin/calc_test

# Run example with integers as command line arguments
./bin/calc_example <engine_name> <list of integers>

# Run example with file of integers (exclude .txt in the file name)
./bin/calc_example <engine_name> <file name>

Options:

• Turn off building tests with cmake -DBUILD_GTEST=OFF ..
• Turn off building documentation with cmake -DBUILD_DOCS=OFF ..
• Build Doxygen docs with make doc

Users can implement their own engines. Simply create a custom class inheriting from BaseEngine, define custom behavior in calc(), and set an allowable input type. To plug into BaseEngine's factory method, add an entry to the EngineType enum list and add a custom switch-case statement to BaseEngine's static create() factory method.