Every now and then someone drags me into a C++ discussion. I have friends who code in C++. Some of them do it for money. I’m sorry about that.

Recently I heard about “const methods”. “What’s that?” I ask; “Methods that are contractually obliged not to change their object.”. Oh, I think. That seems really useful, but a feature like that would never make into C++ (I reason, based on what I know of C). Still, not knowing much about C++ I shut up and go and learn some more C++ instead. I consult my friends who actually know more C++ than I do. The replies are not consistent, not confident, and sometimes go all slippery and vague when I press for details.

Then, it dawns on me. A “const method” is simply a method whose this pointer is const qualified. It’s an inevitable feature of the language…