Keywords

They cannot be used as variable names, function names, or identifiers. Below is a list of keywords in standard C (C89/90, C99, C11):

Control Statements

• if

• else

• switch

• case

• default

Loops

• for

• while

• do

• break

• continue

Data Types

• int

• float

• double

• char

• void

Type Modifiers

• short

• long

• signed

• unsigned

Storage Class Specifiers

• auto

• register

• static

• extern

• typedef

Type Qualifiers

• const

• volatile

• _Atomic (C11)

Memory Management

• sizeof

• return

Structures and Unions

• struct

• union

• enum

Pointers

• goto

Boolean and Miscellaneous

• _Bool (C99)

• _Complex (C99)

• _Imaginary (C99)

Threading (C11)

• _Thread_local

• _Static_assert

• _Alignas

• _Alignof

• _Noreturn

Notes:

1. Keywords may vary slightly depending on the compiler and standard being used (e.g., C89, C99, or C11).

2. _-prefixed keywords (e.g., _Bool, _Thread_local) are introduced in newer standards and should be used with care for compatibility.