/swe_take_home_exercise

Take home exercise for SWE candidates

Prefix & Infix Calculator

Part One

You are to write a program that accepts numerical calculations in prefix notation, such as + 5 7 or - 12 * 2 6.

You can make the following assumptions:

  • The system should support the operators {+, -, *, /} which all take exactly two args.
  • The input literals are positive integers
  • Calculations can be done in the floating-point or integer domain
  • Handling division by zero is unimportant; program can crash or do anything if that arises.
  • You don't need to consider operator presidence
  • You are free to use any programming language of choice but please provide any requirements to run the code EG: Python version or Pip dependencies

Sample input (caret prompt for clarity only):

> 3
3
> + 1 2
3
> + 1 * 2 3
7
> + * 1 2 3
5
> - / 10 + 1 1 * 1 2
3
> - 0 3
-3
> / 3 2
1 (or 1.5)

All assumptions from the previous task hold for this one.

Part Two

Implement your calculator in infix notation with support for full-parenthesized operands. It's OK to assume that all the tokens are space-separated, including the parenethesis tokens

Sample input (caret prompt for clarity only):

> ( 1 + 2 )
3
> ( 1 + ( 2 * 3 ) )
7
> ( ( 1 * 2 ) + 3 )
5
> ( ( ( 1 + 1 ) / 10 ) - ( 1 * 2 ) )
-1 (or -1.8)

Additional Bonus

Create a web-based version of your calculator, as in a service with a RESTful interface. The goal would be to be able to interact with your calculator over the internet vs a standalone desktop based application.

Deliverables:

A GitHub repo with your working code for the prefix and infix versions along with accompanying test cases