C# Questions

I need some help with some C# questions. I am new to C# and don't know much. Can you guys help?

01. If a method does not return a value its return type is?

I recall arguing this for weeks with this guy a year above me on my CS course. He stated that black is not a colour because there is no light, whereas I insisted that it is perception that counts so of course it's a colour. In the end, I gave up arguing with him when I realised that IHBT.

Years later, I got rather drunk at a party, leading me to gravely, truthfully, repeatedly insult him in front of a large group of people, and he never spoke to me again.

Overall, I think that's a win.