C Identifiers

In C programming, identifiers are names given to various program elements such as variables, functions, arrays, and more. These names are used to uniquely identify and reference these elements within your code. Understanding the rules and conventions for creating identifiers is essential for writing readable and maintainable C programs.

In this lesson, we will explore the characteristics, naming conventions, and best practices for using identifiers in C programming.

Rules

• An identifier can be of alphanumeric values only i.e letters and digits. (A-Z, a-z, 0-9)
• Underscore _ can be used in an identifier.
• Identifier names must be unique.
• Keywords cannot serve as an Identifier.
• No special character is allowed.
• The first character of an identifier must be an alphabet or underscore.
• Identifiers are case-sensitive.
• No white spaces are allowed.

Naming Conventions and Best Practices

To write clean and maintainable C code, it’s essential to follow naming conventions and best practices for identifiers. Here are some widely accepted guidelines:

Meaningful Names: Choose descriptive names that convey the purpose or meaning of the element. Avoid overly short or cryptic identifiers.

// Good: descriptive variable name
int totalScore;

// Avoid: overly short or unclear name
int ts;

Camel Case: For multi-word identifiers (e.g., variables or functions), use camel case, where each word is capitalized except the first. This makes the identifier more readable.

// Camel case example
int studentCount;

Uppercase for Constants: Constants, such as macros or global constants, are often written in uppercase letters with underscores separating words.

// Constant example
#define MAX_SCORE 100

• Avoid Underscores at the Start: While C allows identifiers to start with an underscore, it’s generally best to avoid it, as it can be reserved for system or library use.
• Consistent Style: Maintain a consistent naming style throughout your codebase. This helps improve code readability and maintainability.

// Inconsistent style
int playerScore;
float PlayerHeight;

// Consistent style (both camel case)
int playerScore;
float playerHeight;

Use Singular Nouns: For variables representing single items, use singular nouns in the identifier names.#

// Singular noun example
int carSpeed;

Avoid Acronyms: Try to avoid using acronyms or abbreviations unless they are widely recognized and understood.

// Avoid: unclear abbreviation
int compTemp;

// Better: full word
int computerTemperature;

Identifiers play a crucial role in C programming, providing names for various program elements. By following the rules, naming conventions, and best practices outlined in this lesson, you can create code that is not only syntactically correct but also readable and maintainable. Thoughtful and meaningful identifier names can greatly enhance the understanding and collaboration among programmers working on a project.