PHP Functions

PHP User-defined function

PHP functions are blocks of code that perform specific tasks.
PHP has over 700 built in functions.
PHP also support user-defined functions.
Function are use for re-usability of same code for multiple times.


Syntax for PHP functions

Function definition starts with name function.
Function_name can be start with letters or underscore followed by any number of letters, numbers, or underscores.
Function_name can not be start with number.
Function names are case-insensitive.



In above example we create a function having name sum().
All the function body or function code is done within curly brace({});
‘{‘ opening curly brace indicates beginning of function code and ‘}’ closing curly brace indicates the end of the function.
Here we pass $a as argument to function.



  • Functions need not be defined before they are referenced.
  • All PHP functions have global scope.
  • PHP does not support function overloading.
  • Also, it is not possible to redefine the previously-declared functions.
  • It is possible to call recursive functions in PHP.
  • Example

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