Constants in PHP
Constants like
variables are also used to store information. However, the main difference
between variables and constants being that the value of constant cannot be
changed
Constants are
used to lock in values to ensure that they are not modified accidentally
Constants are
used to store mathematical constants, passwords, paths etc...
Constants make it
easier run a program using different values by allowing you to change the
values of constants and running the updated code. This saves the effort of
searching the entire program and changing the value at each instance
Examples:
define("PASSWORD",
admin);
// PASSWORD is
the name of the constant to which the value admin is being assigned.
Script:
Constant.php
<?php
define("PASSWORD",
"admin");
echo (PASSWORD);
echo"</br>";
echo constant ("PASSWORD");
echo"</br>";
echo
"PASSWORD";
?>
Output
admin
admin
Password
Pseudo Types
- Pseudo types are data types used in PHP documentations to explain certain features.
- They do not really exist.
- In PHP programming syntax, you would be seeing pseudo types as follows
