Question

Are the naming conventions similar in different languages? If not, what are the differences?

Answer 1

As others have said, things vary a lot, but here’s a rough overview of the most commonly used naming conventions in various languages:

lowercase, lowercase_with_underscores:

Commonly used for local variables and function names (typical C syntax).

UPPERCASE, UPPERCASE_WITH_UNDERSCORES:

Commonly used for constants and variables that never change. Some (older) languages like BASIC also have a convention for using all upper case for all variable names.

CamelCase, javaCamelCase:

Typically used for function names and variable names. Some use it only for functions and combine it with lowercase or lowercase_with_underscores for variables. When javaCamelCase is used, it’s typically used both for functions and variables.

This syntax is also quite common for external APIs, since this is how the Win32 and Java APIs do it. (Even if a library uses a different convention internally they typically export with the (java)CamelCase syntax for function names.)

prefix_CamelCase, prefix_lowercase, prefix_lowercase_with_underscores:

Commonly used in languages that don’t support namespaces (i.e. C). The prefix will usually denote the library or module to which the function or variable belongs. Usually reserved to global variables and global functions. Prefix can also be in UPPERCASE. Some conventions use lowercase prefix for internal functions and variables and UPPERCASE prefix for exported ones.

There are of course many other ways to name things, but most conventions are based on one of the ones mentioned above or a variety on those.

BTW: I forgot to mention Hungarian notation on purpose.