PHP static Variable Understanding----(add static keyword before variable)

In addition to the use of regular classes and methods in PHP, access control, static keywords, static variables can be local variables can also be global variables, when a program segment is completed, the static variable does not disappear, it still exists in memory, the next time the definition or the previous value , often used in recursive or sub-function to retain the previous value, can be used to define variables and methods, the role is not specific to say, the use of the way, the following simple code:

1<?PHP2 functionAdd$i){3     Static $sum= 0;4     if($i<=100){5         $sum=$sum+$i;6Add$i+1);7     }8     Echo $sum; die;9 }TenAdd (1);

Effect

PHP static Variable Understanding----(add static keyword before variable)