Keywords in C: List of Keywords

What are Keywords?

Keywords are reserved words in C that have a predefined meaning and cannot be used as identifiers (variable or function names).

List of C Keywords (C89 — 32 keywords)

auto, break, case, char, const, continue, default, do, double, else, enum, extern, float, for, goto, if, int, long, register, return, short, signed, sizeof, static, struct, switch, typedef, union, unsigned, void, volatile, while

Key Points

• All keywords in C are written in lowercase.
• Keywords cannot be redefined or used as variable names.
• Later C standards (C99, C11) added more keywords such as inline, restrict, and _Bool.