Object Oriented Programming, Zend Certification

Question: What are the values of $a in $obj_one and $obj_two when this script is executed?<?php
class myClass {
  private $a;

  public function __construct() {
    $this->a = 10;
  }

  public function printValue() {
    print "The Value is: {$this->a}\n";
  }

  public function changeValue($val, $obj = null) {
    if(is_null($obj)) {
      $this->a = $val;
    } else {
      $obj->a = $val;
    }
  }

  public function getValue() {
    return $this->a;
  }
}

$obj_one = new myClass();
$obj_two = new myClass();

$obj_one->changeValue(20, $obj_two);
$obj_two->changeValue($obj_two->getValue(), $obj_one);

$obj_two->printValue();
$obj_one->printValue();

?>
A10,20

BYou cannot modify private member variables of a different class

C20,20

D10,10

E20,10

Note: Not available

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Question: What are the three access modifiers that you can use in PHP objects?
A
protected

B
public

C
static

D
private

E
final

Note: Not available
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Question: When checking to see if two variables contain the same instance of an object, which of the following comparisons should be used?
A
if($obj1->equals($obj2) && ($obj1 instanceof $obj2))

B
if($obj1->equals($obj2))

C
if($obj1 === $obj2)

D
if($obj1 instanceof $obj2)

E
if($obj1 == $obj2)

Note: Not available
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Question: In PHP 5 you can use the ______ operator to ensure that an object is of a particular type. You can also use _______ in the function declaration.
A
instanceof, is_a

B
instanceof, type-hinting

C
type, instanceof

D
===, type-hinting

E
===, is_a

Note: Not available
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Question: What is wrong with the following code?
<?php function duplicate($obj) { $newObj = $obj; return $newObj; } $a = new MyClass(); $a_copy = duplicate($a); $a->setValue(10); $a_copy->setValue(20); ?>
A
You must use return &$newObj instead

B
There is nothing wrong with this code

C
duplicate() must accept its parameter by reference

D
You must use the clone operator to make a copy of an object

E
duplicate() must return a reference

Note: Not available
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Question: How can you modify the copy of an object during a clone operation?
A
Put the logic in the object's constructor to alter the values

B
Implment your own function to do object copying

C
Implement the object's __clone() method

D
Implement __get() and __set() methods with the correct logic

E
Implement the __copy() method with the correct logic

Note: Not available
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Question: What is the primary difference between a method declared as static and a normal method?
A
Static methods can only be called using the :: syntax and never from an instance

B
Static methods do not provide a reference to $this

C
Static methods cannot be called from within class instances

D
Static methods don't have access to the self keyword

E
There is no functional difference between a static and non-static method

Note: Not available
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Question: What is the output of the following script?<?php

class ClassOne {
  protected $a = 10;

  public function changeValue($b) {
    $this->a = $b;
  }
}

class ClassTwo extends ClassOne {

  protected $b = 10;

  public function changeValue($b) {
    $this->b = 10;
    parent::changeValue($this->a + $this->b);
  }

  public function displayValues() {
    print "a: {$this->a}, b: {$this->b}\n";
  }
}

$obj = new ClassTwo();

$obj->changeValue(20);
$obj->changeValue(10);

$obj->displayValues();

?>
Aa: 30, b: 30

Ba: 30, b: 20

Ca: 30, b: 10

Da: 20, b: 20

Ea: 10, b: 10

Note: Not available

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Question: The ______ keyword is used to indicate an incomplete class or method, which must be further extended and/or implemented in order to be used.
A
final

B
protected

C
incomplete

D
abstract

E
implements

Note: Not available
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Question: 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.
A
array, interface

B
interface, implements

C
interface, extends

D
instance, implements

E
access-list, instance

Note: Not available
1. Report

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Question: What are the three access modifiers that you can use in PHP objects?

Question: When checking to see if two variables contain the same instance of an object, which of the following comparisons should be used?

Question: In PHP 5 you can use the operator to ensure that an object is of a particular type. You can also use _ in the function declaration.

Question: What is wrong with the following code?
<?php function duplicate($obj) { $newObj = $obj; return $newObj; } $a = new MyClass(); $a_copy = duplicate($a); $a->setValue(10); $a_copy->setValue(20); ?>

Question: How can you modify the copy of an object during a clone operation?

Question: What is the primary difference between a method declared as static and a normal method?

Question: The ______ keyword is used to indicate an incomplete class or method, which must be further extended and/or implemented in order to be used.

Question: 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.

Question: What are the three access modifiers that you can use in PHP objects?

Question: When checking to see if two variables contain the same instance of an object, which of the following comparisons should be used?

Question: In PHP 5 you can use the ______ operator to ensure that an object is of a particular type. You can also use _______ in the function declaration.

Question: What is wrong with the following code?<?php function duplicate($obj) { $newObj = $obj; return $newObj; } $a = new MyClass(); $a_copy = duplicate($a); $a->setValue(10); $a_copy->setValue(20); ?>

Question: How can you modify the copy of an object during a clone operation?

Question: What is the primary difference between a method declared as static and a normal method?

Question: The ______ keyword is used to indicate an incomplete class or method, which must be further extended and/or implemented in order to be used.

Question: 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.

Question: In PHP 5 you can use the operator to ensure that an object is of a particular type. You can also use _ in the function declaration.

Question: What is wrong with the following code?
<?php function duplicate($obj) { $newObj = $obj; return $newObj; } $a = new MyClass(); $a_copy = duplicate($a); $a->setValue(10); $a_copy->setValue(20); ?>

Question: 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.