49.4 Naming conventions

CONSTANT_CASE

All uppercase letters with words separated by underscores (_).

Global constants, environment variables, and configuration flags across C, Java, Rust, and Python.

MAX_TIMEOUT, DEFAULT_PORT_NUMBER.

Train-Case

Capitalized words separated by hyphens (-).

HTTP headers and specialized configuration keys.

Content-Type, Cache-Control.

camelCase

First word starts with a lowercase letter; every subsequent word starts with an uppercase letter with no spaces or symbols.

Variables, functions, and methods in Java and C#.

firstName, getUserData.

PascalCase

Every word—including the first word—starts with an uppercase letter.

Classes, structures, interfaces, enums, and constructors across C#, Java, Rust and Python.

FirstName, UserProfile.

snake_case

All lowercase letters with words separated by underscores (_).

Variables and functions in Python, Ruby, Rust and PHP.

first_name, calculate_total_price.

kebab-case

All lowercase letters with words separated by hyphens (-).

CSS class/ID names, URLs, HTML attributes, and file/folder names.

user-profile-card, main-content.

Hungarian notation

Prefixes an identifier with a short code indicating its data type or intended purpose.

sUserName for a string, iCount for an integer.

Interface & type prefixes

Prefixing interface names with an I or generic parameters with a T.

IUserService, TKey, TValue.

Boolean prefixes

Prefixing boolean variables or predicate functions with words like is or has.

isUserActive, hasPermission.

Action-based function patterns

Prefixing function names using a set of verb patterns like get/find for retrieving data, set for assigning values, create/read/update/delete for CRUD system, etc.

getFirstName(), set_mode().

Unit suffixes

Appending measurement units to variable names to prevent ambiguity.

timeoutMs, delaySeconds, fileSizeMb.