#AP Computer Science A: Constructors & Object Initialization 🚀

Hey! Let's get you prepped for the AP exam. This guide is designed to be your best friend the night before the test—clear, concise, and super helpful. We'll break down constructors and object initialization, making sure everything clicks into place. Let's do this!

#Constructors & Object Creation

#What's a Constructor? 🤔

Think of a constructor as the object factory 🏭. It's a special method that creates new objects and sets them up with their initial characteristics. When you create a new object, you're essentially calling its constructor.

For example, if we have a Person class, we can create a Person object like this:

java
Person peter = new Person("Peter", 17, 13);

• Person: The class name (usually capitalized).
• new: Keyword to call the constructor.
• ("Peter", 17, 13): The parameter list – values for the object's characteristics.
• peter: The object name (camelCase).

#Key Points to Remember

• Object Creation: The new keyword is essential. It's like saying, "Hey, make a new one of these!"
• Parameter List: These are the initial values for the object's attributes.
• Naming: Class names are capitalized, object names are camelCase.

#Pass-by-Value vs. Pass-by-Reference

Java uses pass-by-value. Here's what that means:

• Primitives (int, double, etc.): A copy of the value is passed. Changes inside the constructor don't affect the original value.
• Reference Types (Objects, Arrays): A reference (memory address) is passed. Changes do affect the original object.