Midterms - Object Oriented Programming in PHP

Question 1

Defining a class

Answer 1

class keyword, class name, curly brace

<?php
class Fruit {

//Properties
public $name;
public $color;

//Methods
function set_name($name){
$this->name = $name;
}

function get_name(){
return $this->name;
}
}
?>

Question 2

Objects of a class are created using the

Answer 2

new keyword

$apple = new Fruit ();

Question 3

refers to the current object, and is only available inside methods.

Answer 3

$this keyword

 <?php
class Fruit {
  public $name;
  function set_name($name) {
    $this->name = $name;
  }
}
$apple = new Fruit();
$apple->set_name("Apple");

echo $apple->name;
?> 

Question 4

using $this keyword to change the value of a property

Answer 4

<?php

class Fruit{
public $name;

function set_name ($name){
$this->name = $name;

}
}

$apple = new Fruit();
$apple->set_name("Apple");

echo $apple->name;
?>

Question 5

ou can use the ____ keyword to check if an object belongs to a specific class:

Answer 5

instanceof

<?php
$apple = new Fruit();
var_dump($apple instanceof Fruit);

Question 6

allows you to initialize an object’s properties upon creation of the object

Answer 6

constructor

function_construct($name){
$this->name = $name;
}

Question 7

is called when the object is destructed or the script is stopped or exited

Answer 7

destruct Function

function_destruct(){
echo "The fruit is ($this->name).";
}

Question 8

the property or method can be accessed from everywhere. This is default

Answer 8

public

Question 9

the property or method can be accessed within the class and by classes derived from that class

Answer 9

protected

Question 10

the property or method can ONLY be accessed within the class

Answer 10

private

Question 11

When a class derives from another class.
The child class will inherit all the public and protected properties and methods from the parent class. In addition, it can have its own properties and methods

Answer 11

Inheritance

Question 12

An inherited class is defined by using the

Answer 12

extends keyword
~~~
class Strawberry extends Fruit {
}
~~~

Question 13

Inherited methods can be overridden by redefining the methods (use the same name) in the child class

Answer 13

Overriding

Question 14

can be used to prevent class inheritance or to prevent method overriding.

Answer 14

final keyword
~~~
final class Fruit{
}
~~~

Question 15

cannot be changed once it is declared

Answer 15

costant

Question 16

Class constants are
A. case sensitive
B. case insensitive

Answer 16

A. case sensitive

Question 17

how to access constant from outside the class?

Answer 17

class name, scope resolution operator (::), constant name
~~~
<?php
class Goodbye{
const LEAVING_MESSAGE = “message”;
}

echo Goodbye::LEAVING_MESSAGE;
?>
~~~

Question 18

how to access constant from inside the class?

Answer 18

self keyword, scope resolution operator (::), constant name

<?php
class Goodbye{
const LEAVING_MESSAGE = "message";
public function byebye(){
echo self::LEAVING_MESSAGE;
}
}
$goodbye = new Goodbye();
$goodbye->byebye();
?>

Question 19

are when the parent class has a named method, but need its child class(es) to fill out the tasks

Answer 19

Abstract Classes

Question 20

is a method that is declared, but not implemented in the code.

Answer 20

abstract method

Question 21

allow you to specify what methods a class should implement.

Answer 21

Interfaces

Question 22

Interfaces are declared with the

Answer 22

interface keyword

<?php
interface InterfaceName{
}
?>

Question 23

____ cannot have properties but ____ can

Answer 23

Interfaces, Abstract classes

Question 24

interface methods must be

Answer 24

public

Question 25

abstract class methods must be

Answer 25

public or protected

Question 26

When one or more classes use the same interface, it is referred to as

Answer 26

polymorphism

Question 27

to implement an interface, a class must use the

Answer 27

implements keyword
~~~
<?php
interface Animal{
public function makeSound()
}

class Cat implements Animal{
public function makesound(){
echo “Meow”;
}
}

$animal = new Cat ();
$animal->makesound();
?>
~~~

Question 28

A user-defined function declaration starts with the

Answer 28

function keyword
~~~
function myMessage(){
echo “Hello World”;
}
~~~

Question 29

Information can be passed to functions through

Answer 29

arguments

Question 30

Arguments are specified after the function name, inside the

Answer 30

parentheses

function familyName($fname){
echo "$fname LastName.<br>";
}
familyName ("John");

Question 31

to let a function return a value use the

Answer 31

return statement

function sum ($x, y$){
$z = $x + $y;
return $z;
}
echo "5+10 = " . sum(5,10) . "<br>";

Question 32

To turn a function argument into a reference, use the

Answer 32

& operator

function add_five(&$value){
$value += 5;
}

$num = 2;
add_five ($num);
echo $num;

Question 33

array function for counting arrays

Answer 33

count ()

$cars = array ("Volvo", "BMW", "Toyota");
echo count ($cars);

Question 34

To access an array item you can refer to the

Answer 34

index number

$cars = array ("Volvo", "BMW", "Toyota");
echo $cars[0];

Question 35

are arrays that use named keys that you assign to them

Answer 35

Associative arrays

$car = array (“brand” => “Ford”, “model” => “Mustang”, “year” => 1964);

echo $car [“model”];