This is a rewrite of a simple project I did in college circa 2006. The original source was lost, so here I am trying to implement a calculator exactly the same way I did back then (I more or less remember that lol). So this is not trying to be a correct implementation, merely nostalgic.
To build using Mono C# compiler, use:
mcs -pkg:glade-sharp-2.0 -resource:calc.glade calc.cs
Then, resulting binary can be run with Mono using:
mono calc.exe