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2026

Advanced Calculator

  • Python
  • Tkinter
  • unittest
  • PyInstaller
  • Inno Setup
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Overview

A standard and scientific desktop calculator inspired by the Windows Calculator, built with Python and Tkinter. Expressions are evaluated by a hand-written recursive descent parser with correct operator precedence, without using eval(). Supports trigonometric functions (degrees/radians), logarithms, factorial, percentages and implicit multiplication. Includes a history panel, memory keys, light/dark themes and Windows-compatible keyboard shortcuts. Covered by 17 unit tests and distributed as a Windows installer built with PyInstaller and Inno Setup.

01 · Problem

Most calculator projects evaluate expressions with eval(). That is unsafe and skips the genuinely hard parts: operator precedence, implicit multiplication and floating-point errors.

02 · Solution

I wrote a recursive descent parser that first splits the expression into tokens and then handles each precedence level in its own function. Evaluation, formatting, history and the UI live in separate modules; the Tkinter interface offers standard and scientific modes, a history panel, memory keys, light/dark themes and Windows-compatible keyboard shortcuts.

03 · Outcome

The evaluation engine is verified by 17 unit tests and correctly shows results such as 0.1 + 0.2 = 0.3 and sin(180°) = 0. The app ships as an installer built with PyInstaller and Inno Setup, so it runs on computers without Python.