1. Naming Rules

Variable names in C must adhere to certain rules:

• Can contain letters (both uppercase and lowercase), digits, and underscores (_).
• Must begin with a letter or underscore, not a digit.
• Are case-sensitive (total and Total are different).
• Cannot be a reserved keyword (e.g., int, return).

2. Best Practices for Variable Names

Adopting good naming conventions improves code clarity:

• Use meaningful names that describe the variable's purpose.
• Follow a consistent naming style (e.g., camelCase, snake_case).
• Avoid overly long or short names.
• Use lowercase letters for variable names; uppercase is typically used for constants.

3. Examples of Good and Bad Variable Names

Good Variable Names	Bad Variable Names
totalSum	ts
numberOfStudents	n
averageScore	a_s
isValid	v
userName	u1

Best Practices

• Choose variable names that convey meaning.
• Stick to a consistent naming convention.
• Use comments to explain the purpose of variables if necessary.

Don'ts

• Don't use single-letter names except in loops (e.g., i, j).
• Don't start variable names with a digit.
• Don't use special characters other than the underscore.
• Don't use variable names that are too similar (e.g., data1, data2).

Key Takeaways

• Variable names must follow C's naming rules to be valid.
• Good naming practices improve code readability and maintainability.
• Consistent naming conventions are important in collaborative environments.