CPP

Lecture 2 : Identifiers

• Contants
• Variables
• Keywords
• Data Types

1. Contants

• any information is constant
• Data = Information = Constant

Types of Constants

1. Primary
   • Integer (5,100,-64,79,106)
   • Real (5.0, 1.06)
   • Character (‘A’, ‘5’, ‘+’)
2. Secondary
   • Array
   • String (“Priyanshu”)
   • Pointer
   • Union
   • Structure
   • Enumerator
   • Class

2. Variables

• variables are the names of memory locations where we store data
• variable name is any combination of alphabet (a to z or A to Z), digit (0 to 9) and underscore (_)

3. Keywords

• predined words used to perform certain operations

auto	double	int	struct	asm	private
break	else	long	switch	catch	public
case	enum	register	typedef	class	protected
char	extern	return	union	delete	template
const	float	short	unsigned	friend	this
continue	for	signed	void	inline	throw
default	goto	sizeof	volatile	new	try
do	if	static	while	operator	virtual

4. Data types

• int (integer)
• char (Character)
• float (Real)
• double (Real)
• void

Unlike C, we can declare variables even after action statements in C++

Example :

int main()
{
    clrscr();
    int x=4;
}