Output of the following code:  <?php class A {} class B {} class C extends B {}  class D {   function sayHello (A $argument) {     echo '$argument is an instance of A'   }    function sayHello (B $argument) {     echo '$argument is an instance of B'   } }  $d = new D(); $c = new C();  $d->sayHello($c);

What prefix prevents child classes from overriding a method

Best way to iterate and modify every element of an array using PHP 5?

$sweet = array('1' => 'apple', '2' => 'banana'); $fruits = array('delicious' => $sweet, 'sweet' => 'strawberry'); function myprint($item, $key) { echo '$key is $item\n'; } array_walk_recursive($fruits, 'myprint'); In above code, what is the output?

To ensure that a given object has a particular set of methods, you must provide a method list in the form of an ________ and then attach it as part of your class using the ________ keyword.

Output of the following code? $arr = 'a'; $arr[0]='b'; echo $arr; echo $arr[0];

for($a=0,$b=20; $a<50; $a++) { while($b--) { if($b==8) goto end; } } echo 'a = $a'; end: echo ?>

var_dump(0 == 'x'); var_dump('2' == '02'); var_dump('20' == '2e2'); var_dump(200 == '2e4'); switch ('x') { case 0: echo '0'; break; case 'x': echo 'x'; break; } ?>

class First { private $foo = 2; protected $bar = 4; protected function A_funct() { return 5; } public function B_funct() { return new class($this->foo) extends First { private $test; public function _construct($foo) { $this->test = $foo; } public function C_funct() { return $this->bar + $this->test + $this->A_funct(); } }; } } echo (new First)->B_funct()->C_funct();?>

Which cast option can be used for explicitly converting a value to integer?

Which is the correct output of the following PHP 7.1 program? function swap(&$x, &$y): void { if ($x === $y) { return; } $exp = $x; $x = $y; $y = $exp; } $var1 = 12; $var2 = 20; var_dump(swap($var1, $var2), $var1, $var2);?>