https://github.com/unoplatform/rpncalculator

The Xamarin.Forms RPN (Reverse Polish Notation) calculator running in WebAssembly
https://github.com/unoplatform/rpncalculator

csharp first-timers-friendly mono sample uno uno-platform wasm webassembly xamarin xamarin-forms

Last synced: 4 months ago
JSON representation

The Xamarin.Forms RPN (Reverse Polish Notation) calculator running in WebAssembly

• Host: GitHub
• URL: https://github.com/unoplatform/rpncalculator
• Owner: unoplatform
• License: other
• Created: 2019-09-05T17:14:01.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2023-01-16T10:01:47.000Z (over 2 years ago)
• Last Synced: 2023-03-11T20:49:27.842Z (over 2 years ago)
• Topics: csharp, first-timers-friendly, mono, sample, uno, uno-platform, wasm, webassembly, xamarin, xamarin-forms
• Language: C#
• Homepage: https://rpncalculator-wasm.azurewebsites.net/
• Size: 1.11 MB
• Stars: 10
• Watchers: 5
• Forks: 3
• Open Issues: 12
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
---

name: Xamarin.Forms - RPN Calculator

description: An RPN (Reverse Polish Notation) calculator allows numbers and operations to be entered without parentheses or an equal key. RPN (also called...

page_type: sample

languages:

- csharp

products:

- xamarin

urlFragment: rpncalculator

---

# RPN Calculator

An RPN (Reverse Polish Notation) calculator allows numbers and operations to be entered without parentheses or an equal key. RPN (also called postfix notation) is described in the Wikipedia article [**Reverse Polish notation**](https://en.wikipedia.org/wiki/Reverse_Polish_notation) and the [**RPN Calculator**](https://github.com/xamarin/Workbooks/blob/master/xamarin-forms/advanced/RPNCalculator/RpnCalculator-ios.workbook) workbook, which shows an alternative approach to coding an RPN calculator for Xamarin.Forms.

RPN is based on a stack. Numbers are pushed on the stack by pressing the ENTER key. Unary operations (such as **log** and **sin**) pop a number from the stack, apply the operation, and push the result back on the stack. Binary operations (such as **+** and **/**) pop two numbers from the stack, perform the operation, and push the result on the stack.

To perform the calculation

5 × (3 + 4) – 2

press the following keys:

5 ENTER 3 ENTER 4 ENTER + × 2 ENTER –

The + operation adds 3 and 4, the times operation multiplies 5 and that result, and the minus operation subtracts 2 from that result.

The layout of the keys appears twice in the **MainPage.xaml** file, separately for portrait mode and landscape mode. The **MainPage.xaml.cs** code-behind file switches between these two layouts based on the relative width and height of the page.

The calculator logic is encapsulated in the **RpnCalculatorViewModel.cs** file. The XAML file and the ViewModel are linked through XAML-based data bindings, which are described in detail in the series of series of articles on [**Data Binding**](https://docs.microsoft.com/xamarin/xamarin-forms/app-fundamentals/data-binding/), and particularly the [**The Command Interface**](https://docs.microsoft.com/xamarin/xamarin-forms/app-fundamentals/data-binding/commanding) article.

![RPN Calculator application screenshot](Screenshots/01Portrait.a.png "RPN Calculator application screenshot")

## Author

Charles Petzold