Python expression calculator

This calculator allows you to calculate mathematical expressions. Various mathematical functions, trigonometric functions and operations are supported. Parentheses are supported for grouping expressions.

Features

• Arithmetic operations:
  • addition (+)
  • subtraction (-)
  • multiplication (*)
  • division (/)
  • exponentiation (^)
  • remainder (%)
• Trigonometric functions:
  • sin (sin)
  • cos (cos)
  • tan (tan)
  • cot (cot)
• Other mathematical functions:
  • natural logarithm (ln)
  • square root (sqrt)
  • factorial (fact or !)
  • logarithm with custom base (log(a, b))
  • minimal of two (min(a, b))
  • maximum of two (max(a, b))

Algorithm base

The algorithm is based on tokenizing input expression and sorting tokens in Shunting yard algorithm (https://en.wikipedia.org/wiki/Shunting_yard_algorithm). The expression is converted to a string of postfix notation, also known as reverse Polish notation (RPN), and then its result is calculated.

Technologies used

• Basic language is Python with GUI on Tkinter and math and numpy modules for logic
• Tests are written on unittest
• Behavior Driven Development (BDD) is written on Behave framework