CalcPlusPlus - A Modern Qt6 C++ Scientific Calculator

Table of Contents

• Overview
• Features
  • Core Functionality
  • Expression Display
  • Interactive History
  • Error Handling
  • Design & User Interface
• Installation Guide
  • Option 1: Install from .deb package (Recommended)
  • Option 2: Build Manually
• Technical Details
• License
• Author

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Overview

CalcPlusPlus is a professional, modern, and intuitive scientific calculator application developed using C++17 and the Qt6 framework. Designed for Linux (Ubuntu 22.04+), it offers a clean user interface, responsive layout, and persistent calculation history, making it a reliable tool for both basic and advanced mathematical operations.

• Version: v1.0.0
• Platform: Linux (Ubuntu 22.04+)
• Built with: C++17, Qt6 (Widgets, Core, GUI, SQL), CMake, SQLite
• Packaging: .deb installer generated via CPack

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Features

Core Functionality

• Comprehensive Operations: Perform addition, subtraction, multiplication, division, percentages, exponentiation (x^y), and square roots.
• Precision Handling: Supports decimal values and negative numbers with double-precision floating-point arithmetic.
• Robustness: Includes integrated error handling to gracefully manage invalid expressions and mathematical exceptions like division by zero.

Expression Display

CalcPlusPlus features an intuitive dual-line display for clarity:

• Top Line: Shows the full mathematical expression as it's being entered or processed (e.g., 75 × 3 + 2).
• Bottom Line: Displays the current number being input or the partial/final result (e.g., 227).
• Post-Calculation View: After pressing the equals button (=), the complete expression (e.g., 75 × 3 + 2 =) remains visible in a smaller, semi-transparent style above the final result, providing a clear record of the performed calculation.

Interactive History

A dedicated history panel, integrated seamlessly as a QDockWidget, provides a comprehensive record of all past calculations:

• Persistent Storage: All operations (expression and result) are automatically saved to a local SQLite database (calc_history.db), ensuring history is retained across application sessions.
• Scrollable List: Displays entries in a scrollable list, with each item showing the operation and its result.
• Recall Functionality: Clicking any history entry loads that specific expression and its result back into the main calculator display, allowing users to easily reuse or continue from previous calculations.
• Clear History: A convenient "Clear History" button is available within the panel to delete all stored entries.

Error Handling

• User-Friendly Alerts: Replaces generic system message boxes with custom-styled alert dialogs that match the application's dark theme.
• Clear Feedback: Provides user-friendly error messages for invalid expressions, mathematical exceptions (e.g., sqrt(-1)), and operational issues.

Design & User Interface

• Modern Dark Theme: Features a sleek dark theme with consistent typography, spacing, and color palette for an aesthetically pleasing experience.
• Responsive Layout: The window layout is designed to adapt gracefully to different display sizes, maintaining usability and visual appeal.
• Intuitive Button Arrangement: Buttons are arranged in a standard, easy-to-use calculator layout for efficient input.

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Installation Guide

Option 1: Install from .deb package (Recommended)

The easiest way to install CalcPlusPlus on Ubuntu 22.04+ is by using the provided Debian package.

1. Download the .deb file: Obtain the latest calcplusplus_1.0.0_amd64.deb file from the Releases page.

2. Install the package: Open a terminal in the directory where you downloaded the .deb file and run:

   sudo dpkg -i calcplusplus_1.0.0_amd64.deb
   sudo apt install -f # To resolve any missing dependencies

3. Launch CalcPlusPlus: Once installed, you can launch CalcPlusPlus from your system’s applications menu (look under "Utilities" or "Calculator") or by typing the command:

   CalcPlusPlus

Option 2: Build Manually

If you prefer to build CalcPlusPlus from source, follow these steps:

1. Install Dependencies: Ensure you have the necessary build tools and Qt6 development libraries installed:

   sudo apt update
   sudo apt install qt6-base-dev qt6-base-dev-tools libsqlite3-dev cmake g++ ninja-build

2. Clone the Repository:

   git clone https://github.com/CodeWithBotinaOficial/CalcPlusPlus.git
   cd CalcPlusPlus

3. Build the Project:

   cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/usr/lib/x86_64-linux-gnu/cmake/Qt6
   cmake --build build --config Release

4. Run the Executable:

   ./build/CalcPlusPlus

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Technical Details

• Project Structure:
  • src/core: Contains the core mathematical logic and the SQLite database manager.
  • src/ui: Manages the Qt Widgets-based user interface and window components.
  • src/utils: Provides utility classes for error handling and custom alerts.
  • resources/: Stores application assets like icons and desktop entry files.
• Build System: CMake is used for cross-platform build configuration, with Ninja as the build tool.
• Database: SQLite3 is integrated for persistent storage of calculation history, automatically managed on application startup.
• Release Automation: GitHub Actions are configured to automate the build process, generate .deb packages, and publish them to GitHub Releases and GitHub Packages upon new tag pushes.

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License

This project is licensed under the MIT License. See the LICENSE file for details.

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Author

© 2025 Diego Alejandro Botina — CodeWithBotina