variables and keywords

C variables :

• an entity that may vary during program execution is called a variable.

Rules for constructing variable names :

• A variable name is any combination of alphabets and can contain upto 31 characters. 
• The first character must be an alphabet or underscore.
• No commas or blanks are allowed.
• No special symbol other than underscore can be used.
• eg. si_intel, m_hrs, rms895.

C Keywords :

• Keywords are the words whose naming has already been explained to the C Compiler.
• Keywords are also called Reserved words.
• There are 32 keywords available in C.
• These keywords are as follows.

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

C programming language is also called a free form language.
Every C statement must end with a semicolon (;) Thus semicolon acts as a terminator.
Comment about the program should be enclosed within /* */ A comment can split over more than oneline as in, /* This is a jazzy comment */ Such a comment is often called a multi line comment.