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A blog site which I am posting to during my learning of the popular programming language PHP. Feel free to leave comments!

• PHP - Constants

  Posted on April 6th, 2009 admin 1 comment

  A constant in PHP stores a value like a variable but if a Constant is given a value it can’t be changed in the script.

  To declare a constant you have to set it out in the following way. Let’s say we wanted to give a chocolate cake a fixed price:

  define(’CHOCOLATECAKE’, 1.50);

  or even a swiss roll! ummm

  define(’SWISSROLL’, 1.25);

  If you wanted to use  a constant all you have to do is use the name of the Constant such as:

  echo CHOCOLATECAKE;

  or even:

  echo SWISSROLL;

  Using these Constants will obviously output the price to the browser. You can use these constants to work out the total cost of both by using Variables and Constants together:

  $totalcost = CHOCOLATECAKE + SWISSROLL;

  The $totalcost now has a value of 2.75 and subsequently this variable is now of the ‘float’ data type as it’s a decimal number. You can see why PHP is a very good language to build customer order forms etc. You now have a variable that has a value and we can now output this to the browser:

  echo “Total cost of your order: £” . $totalcost . “. Thanks for visiting!”;

  As you can see you can effectively use constants and variables together!

  (Post created on Monday, April 6th 09 at 14:15)

  PHP Constants, Declaring Constants, Float, Variables