There are various popular naming conventions which are common among various languages, the relevance of these conventions comes from , the legacy which they hold and other factors like readability, purpose, programming cababilities, for example , we most follow camelcase for java, for c++ which comes with great capabilities, we use lowercase with underscores, most of the time.

why important ?

there are two main advantage which comes with this,

1. consistency in the code base - especially you are contributing open source.
2. readability - with common coding style and following it becomes easy for you to understand the code.

C++ naming convention -

1. Variables - lowercase with underscores,
2. Functions - lower case with underscores,
3. Classes - Pascal case
4. Constants - uppercase with underscores.

In gist : following the best practices , and guidelines, make the job easier for everyone.