• Every C word is classified as a Keyword or an Identifier
• All keywords have fixed meaning which can not be changed
• ANSI has provided 32 basic keywords
• All are lowercase
• Compilers usually add few more KWs
• 32 basic keywords are listed below

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

Identifiers