This will be the output- Fatal error: Call to undefined function b(). You cannot call a function which is inside a function without calling the outside function.

This will be the output- I am a Fatal error: Cannot redeclare b()

If u want to put some variables in function that was not passed by it, you must use "global. Inside the function type global $op2.

It is possible to call a function using a variable which stores the function name.

PHP functions that start with a double underscore “ a "__ “ are called magic functions in PHP. They are functions that are always defined inside classes, and are not stand-alone functions.

func_get_argc()

glob()

The fileatime() function returns a file's last access time in Unix timestamp format or FALSE on error.

file()

bytes