keywords and Identifiers in C

1)    Keywords

• Keywords are the words whose meaning has already been explained to the C compiler and their meanings cannot be changed.
• The keywords are also known as ‘Reserved words’.
• Keywords cannot be used as user-defined variables.
• All keywords must be written in lowercase.
• 32 keywords available in C.

A list of 32 keywords in the c language is given below:

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

 

2)     Identifiers

• Identifiers are names for entities such as variables, functions & arrays.
• An identifier can be consists of only letters (uppercase & lowercase), digits and only one special symbol i.e. underscore.
•  Identifiers should start only with an alphabet or an underscore.
• Keywords not use as identifiers.
• In Identifiers white space not allow