Definitions of constants in PHP _php tutorial

1. Custom Constants
* Must be defined with function define ()
* The value can no longer be changed after the definition is complete.
* Use the constant name directly, not the same as the variable in the front plus $s
For example: Define ("PI", 3.14); Define a constant
$area = Pi*r*r; Calculate the area of a circle
Define ("URL", "http://www.ybldcc.com");
echo "My URL is:". URL;
2 System constants:
File:P hp program filename
Line:P HP program file lines
Php_version: The version number of the current parser
Php_os: Executes the current PHP version of the operating system name
Author "iteamsky-Yang Bo's technical Space"

http://www.bkjia.com/PHPjc/478666.html www.bkjia.com true http://www.bkjia.com/PHPjc/478666.html techarticle 1. Custom constants * must be defined with function define () * After definition, its value can no longer be changed * Use the constant name directly, not as a variable in front of the $s such as: define (pi,3.14 ...

