README.md

June 16, 2026 · View on GitHub

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Simple Calculator is a native Windows 11 application built with C#, WinUI 3, and the MVVM pattern. Its goal is to provide an alternative to the default Windows Calculator. While the default app evaluates inputs step-by-step, this app works like a real physical calculator: you type the entire equation first and press = to calculate the final result.

📖 Project History & Architecture

The first version of this project v1.0.0 was written in WPF. For version v2.0.0, the UI framework and the code structure were changed:

  • WinUI 3: Replaced WPF controls with Windows App SDK components (like NavigationView).
  • MVVM: Separated the mathematical logic from the user interface. The code is divided into Models, Views, and ViewModels. They communicate via data binding and commands.

⚙️ Core Mechanics

Expression Input in Standard Mode

The default Windows Calculator calculates a result after every operator. This app works like a real physical calculator (like a Casio). You type the whole equation exactly as you write it on paper (e.g., (5 + 3) * 8 / 2). It calculates everything at once when you press =. This guarantees the correct mathematical order of operations.

Currency Converter

The app downloads daily exchange rates as an XML file from the European Central Bank (ECB). It uses an XmlReader to parse the data directly into a C# dictionary to calculate currency conversions. The base currency is the Euro (EUR).

🛠️ How to Run

1. Prerequisites

To build and run this project, it is highly recommended to use Visual Studio 2022 (Version 17.0 or later). Before opening the solution, make sure you have the following workloads installed via the Visual Studio Installer:

  • .NET Desktop Development
  • Windows application development (Make that the "Windows App SDK C# Templates" are checked in the optional components on the right side).

2. Clone the Repository

git clone https://github.com/cechout/simple-calculator.git

3. Build and Run

  • Open the solution file in Visual Studio.
  • Right-click on Calculator_WinUI in the Solution Explorer and select Set as Startup Project.
  • In the top toolbar, change the Solution Platform from Any CPU to your specific system architecture (e.g., x64). Note: WinUI 3 projects do not support 'Any CPU' builds.
  • Press F5 to build and run the application.

And now you're good to go!