CamelCase
There is snake_case, also known as using underscores, typically just with lowercase naming
There's also using capitals. I've always known this as CamelCase
...but there is a useful distincition between lowerCamelCase and UpperCamelCase (then a.k.a. PascalCase),
(A few wikis that like to make things links without markup, which then have a more explicit WikiCase, which is UpperCamelCase that can't be one letter long.)
There's also a few languages that allow this-kind-of-naming which has even more names.
underscores versus camelcase is one of those arguments withing the programming world, mostly arguing about which is easier to type and/or read.
In the languages I work in, people seem to agree that
CONSTANTS ClassNames variable_names
but they disagree between
functionNames function_names
Other naming conventions
The point of the distinctions are often to make it easier to guess the purpose or type of a thing based on just the name, rather than having to check.
In that area there are further conventions, like
- using _ for variables you'll ignore
- using
- is_something or has_something for a human-readable suggestion that something returns a boolean
- do_something to suggest it's something and probably with side effects
https://en.wikipedia.org/wiki/Naming_convention_(programming)#Multiple-word_identifiers