PHPGurukul

PHP Constants

Constants are variables
Constants are variables except that once they are defined they can’t be changed or undefined.

  • A constant is an identifier (name) for a simple value. The value cannot be changed during the script.
  • A valid constant name starts with a letter or underscore.
  • (no $ sign before the constant name).
  • Note: Unlike variables, constants are automatically global across the entire script.

Create a PHP constant

  • You can create a constant by using the define () function.
  • Use the define function to specify the name and value of a constant. (name, value, case-insensitive).
  • Many programmers use capital letters to name constants – so they stand out.
  • Note: Since a constant can not be change you do not use a $ sign before it’s name when you declare it or (use it).

 Parameters 
name: Specifies the name of the constant
value: Specifies the value of the constant
case-insensitive: Specifies whether the constant name should be case-insensitive. Default is false
How to declare constants
Examples:

define(‘male’, ‘m’) ;    // a string
constantdefine(‘PI’, 3.14159) ;  // a double constant

PHP Constant Examples

<!DOCTYPE html>
<html>
<body>
<?php// case-sensitive constant namedefine("GREETING", "Welcome to PHPGURUKUL.com!");
echo GREETING;?>  
</body>
</html>

Output: Welcome to PHPGURUKUL.com!

Anuj Kumar

This is Anuj Kumar. I’m a professional web developer with 4+ year experience. I write blogs in my free time. I love to learn new technologies and share with others.
I founded PHPGurukul in September 2015. The main aim of this website to provide PHP, Jquery, MySQL, PHP Oops and other web development tutorials.
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