day 2 variables and constants...

constants:- it is does not change its value at the run time is known as constants.
how to define a constants with example with syntax:-

syntax:-

define ("constant_name','constant_value');

example:-define (pie,3.14);

data types :-

1. 1. integer 

      float value

      string

      boolen 

      null

      note:-if in php the value given in (' ') quotes it is treats as a strings.

      variables: -

      change it value at run time it is known as variables

      syntax:-  $variable_name=value;

      how to use a variables:

      $variables_name ;

      operators:-1.assignments

      2.  arithmatic 3. condition 4. logical

      example:<?php

                      $a+=5;

                     $a=$a+5;

                     $y=$a;

      echo"$y=";

      ?>