I took courses 20+ years ago on C++. So learning C# would not be difficult. I downloaded Visual C# 2010 and 2013 Studio. I found C# is extremely easy because much of the work is done for you. The libraries are more robust. Many of the programs we wrote by hand like sorting arrays are now actual functions. I belong to the IEEE and IEEE Computer Society. The IEEE Computer Society has thousands of books and courses on their site to use. I found a book on C#. I have used many of the books and courses to learn from over the last 20 years of membership. It was a benefit of my B.EE. We were all signed up as students. I consider it continuing education.
This is a 3D multiplication table.
I took a 3D array and added header fields. You take the five sets and stack them in order. You get 0 to 3 on X,Y and Z axis. The tables create a 3D multiplication cube.