How can we take advantage of predefined constants ?

[iannjiua]

PHP features a large number of built-in, predefined constants holding various useful values. Some of these are always available, while other constants become available when certain PHP extensions are enabled. How can we take advantage of predefined constants ? Your ways ?

[delois]

I think there are lots of things present in PHP which we can utilize only when we have requirement. Consider the simple example of making currency converter, with help of these constants you can define value to one global parameter to store value of different currency and use it in programming whenever is require.