A free app for Android, by Kappsmart.

You can use the C Programming Compiler for Windows to create and run your C# programs without having to install any additional software. You can use the built-in text editor to write your code, and the same editor that you use to edit your C# source code also works as a code review tool. You can view the results of your program and find any problems in your code. You can use the Advanced Compiler Option to specify the maximum running time, and you can also customize the C# code editor.