Engineering Calculator

A desktop engineering calculator built with Python + tkinter. Clean dark UI, full scientific function set, persistent history, and keyboard support.

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Features

• Basic arithmetic — + − × ÷
• Scientific functions — sin cos tan cot √ log ln exp x! xʸ x² 1/x
• Constants — π and e
• Memory — MC MR M+
• Modulus and percent — mod %
• Calculation history — saved to history.json, viewable and clearable in-app
• Keyboard input — digits, operators, Enter, Backspace, Escape
• Error handling — friendly messages for division by zero, invalid input, undefined trig values

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Project Structure

engineering_calculator/
│
├── main.py                  # Entry point
├── requirements.txt         # Dependencies
├── README.md
├── history.json             # Auto-generated history file
│
├── calculator/
│   ├── __init__.py
│   ├── basic.py             # add, subtract, multiply, divide
│   ├── scientific.py        # sin, cos, tan, cot, sqrt, log, exp, factorial, power, modulus
│   └── history.py           # History class — saves/loads JSON
│
├── gui/
│   ├── __init__.py
│   ├── app.py               # Main window, all UI logic
│   └── styles.py            # Colors, fonts, sizes
│
└── tests/
    ├── __init__.py
    ├── test_basic.py
    └── test_scientific.py

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Installation

# 1. Clone the repo
git clone https://github.com/sxcred666/Engineering_Calculator.git
cd Engineering_Calculator

# 2. Create virtual environment
python -m venv venv
venv\Scripts\activate        # Windows
source venv/bin/activate     # macOS / Linux

# 3. Install dependencies
pip install -r requirements.txt

# 4. Run
python main.py

Requirements: Python 3.10+, tkinter (bundled with Python)

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Keyboard Shortcuts

Key	Action
0–9 .	Number input
+ - * /	Arithmetic operators
%	Percent
Enter	Calculate =
Backspace	Delete last digit
Escape	Clear all C

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Running Tests

pip install pytest
pytest tests/ -v

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What Changed in Latest Refactor

gui/app.py — rewritten from scratch

• Added missing buttons: log ln exp x! xʸ x² 1/x cot mod % π e ( )
• Added memory: MC MR M+
• Added keyboard support
• Added history popup window with scroll and clear button
• Connected history.py — now actually saves every calculation
• Hover effects on all buttons
• Smart display — shrinks font for long numbers
• Removed all error print() calls — errors show on display instead

gui/styles.py — modern dark theme

• Replaced Soviet theme with clean dark palette
• Purple accent #6C63FF, dark background #0F0F13
• Monospace Consolas font throughout

calculator/basic.py and calculator/scientific.py

• Removed print() from all functions — GUI handles error display
• All functions return None on invalid input

calculator/history.py

• Added MAX_RECORDS = 1000 cap to prevent unbounded file growth
• No other changes — was already correct

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License

MIT