Есть ли разница в написании имени функции в нижнем регистре и в верхнем?

Yes, there is a difference between writing function names in lowercase and uppercase, but it depends on the programming language and its conventions. In many languages, function names are case-sensitive, meaning myFunction and MYFUNCTION are considered different identifiers. For example, in Python or JavaScript, calling a function with a different case than its definition will cause an error.

In some languages or contexts, uppercase function names might be used for constants or macros (like in C), but generally, the case affects how the function is recognized by the compiler or interpreter. Therefore, consistent naming and adherence to language-specific conventions are important to avoid bugs.