Null coalescing operator (??) has been introduced in PHP 7.This is replacement of ternary operator in conjunction with isset() function.It (??) returns its first operand if it exists and not NULL; otherwise it returns its second operand.
$varible = $a ?? $b; // return value of $a if it exist and not null.
<?php // if $_GET['salary'] does not exist.It will return 100000. $salary = $_GET['salary'] ?? '100000'; // This is equivalent to: $salary = isset($_GET['salary']) ? $_GET['salary'] : '100000'; ?>
Scalar type declarations has been introduced in PHP 7. Scalar type declaration has following two option.
session_start() is Old function of PHP.But from PHP 7 session_start() function accepts an array of options.
n Older PHP version (PHP 5 >= 5.3.0), if we want to import Classes,constants and functions from the same namespace then we have to use the "use" statement multiple times.