Purpose of singletons in programming

Question

This is admittedly a rather loose question. My current understanding of singletons is that they are a class that you set up in such a way that only one instance is ever crea

Answer 1

Not all languages have "static classes" (for example C++ doesn't have them).

Again with the C++ example, adding static variables to a class is a pain because you need to put them in both the header and the .cpp file, so a singleton in that case is very useful.

Every language is different. I guess in C# they are not very useful (and in fact, from what I know, they are not used very often)