Case sensitivity in PHP | Php Case sensitivity

Case sensitivity means Words with capital letters do not always have the same meaning when written with lowercase letters.
Case sensitivity also play important role in PHP.
Followings are Case sensitive for both in user defined and PHP defined..

• variables ($var, $Var both are different)
• constants
• array keys
• class properties
• class constants

also OOPs concept in PHP are case sensitive for both user defined as well as PHP defined case..

• functions
• keywords and constructs (if, else, foreach, while, echo etc.)
• class methods
• class constructors