Object instantiation with new in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the new keyword do in PHP?

The <code>new</code> keyword creates a new instance (object) of a class. It tells PHP to build a fresh object based on the class blueprint.

beginner

How do you create an object from a class named <code>Car</code>?

You write $myCar = new Car();. This makes a new Car object and stores it in the variable $myCar.

beginner

What is the difference between a class and an object?

A class is like a blueprint or recipe. An object is the actual thing made from that blueprint. Using <code>new</code> turns the blueprint into a real object you can use.

beginner

Can you instantiate a class without using <code>new</code> in PHP?

No, in PHP you must use <code>new</code> to create an object from a class. Without <code>new</code>, you only have the class definition, not an object.

intermediate

What happens if you call <code>new</code> on a class with a constructor that requires parameters?

You must provide the required parameters inside the parentheses. For example, new Car('red', 2020);. Otherwise, PHP will give an error.

What does $obj = new MyClass(); do in PHP?

A Creates a new object of MyClass

B Deletes the MyClass definition

C Calls a function named MyClass

D Assigns a string 'MyClass' to $obj

Using new creates a new object from the class named MyClass.

Which keyword is used to create an object from a class in PHP?

A create

B object

C new

D make

The new keyword is used to instantiate (create) objects from classes.

What will happen if you forget parentheses when instantiating a class like new Car;?

A It will call the class as a function

B It will cause a syntax error

C It will create a string instead

D It will create the object anyway

In PHP, parentheses are optional if the constructor has no parameters, so new Car; works.

If a class constructor requires parameters, what must you do when using new?

A Call the constructor separately after new

B Pass the required parameters inside parentheses

C No parameters are needed

D Use a different keyword than new

You must provide the required parameters inside the parentheses when calling new.

What is stored in the variable after $obj = new ClassName();?

A An object instance of ClassName

B The class code

C A string 'ClassName'

D Nothing, it's empty

The variable holds the new object created from the class.

Explain in your own words what happens when you use the new keyword in PHP.

Think about turning a recipe into a cake.

Describe how you would create an object from a class that has a constructor with parameters.

Remember how you give ingredients when baking.