Computer Science A
  • Introduction
  • Overview
  • Course at a Glance
  • Course Exam and Description
  • Quick Reference Sheet
  • Unit 1 Primitive Types
    • 1.1 Why Programming? Why Java?
    • 1.2 Variables and Data Types
    • 1.3 Expressions and Assignment Statements
    • 1.4 Compound Assignment Operators
    • 1.5 Casting and Ranges of Variables
  • Unit 2 Using Objects
    • 2.1 Objects: Instances of Classes
    • 2.2 Creating and Storing Objects (Instantiation)
    • 2.3 Calling a Void Method
    • 2.4 Calling a Void Method with Parameters
    • 2.5 Calling a Non-void Method
    • 2.6 String Objects: Concatenation, Literals, and More
    • 2.7 String Methods
    • 2.8 Wrapper Classes: Integer and Double
    • 2.9 Using the Math Class
  • Unit 3 Boolean Expressions and if Statements
    • 3.1 Boolean Expressions
    • 3.2 if Statements and Control Flow
    • 3.3 if-else Statements
    • 3.4 else if Statements
    • 3.5 Compound Boolean Expressions
    • 3.6 Equivalent Boolean Expressions
    • 3.7 Comparing Objects
  • Unit 4 Iteration
    • 4.1 while Loops
    • 4.2 for loops
    • 4.3 Developing Algorithms Using Strings
    • 4.4 Nested Iteration
    • 4.5 Informal Code Analysis
  • Unit 5 Writing Classes
    • 5.1 Anatomy of a Class
    • 5.2 Constructors
    • 5.3 Documentation and Comments
    • 5.4 Accessor Methods
    • 5.5 Mutator Methods
    • 5.6 Writing Methods
    • 5.7 Static Variables and Methods
    • 5.8 Scope and Access
    • 5.9 this Keyword
    • 5.10 Ethical and Social Implications of Computing Systems
  • Unit 6 Array
    • 6.1 Array Creation and Access
    • 6.2 Traversing Arrays
    • 6.3 Enhanced for Loop for Arrays
    • 6.4 Developing Algorithms Using Array
  • Unit 7 ArrayList
    • 7.1 Introduction to ArrayList
    • 7.2 ArrayList Methods
    • 7.3 Traversing ArrayLists
    • 7.4 Developing Algorithms Using ArrayLists
    • 7.5 Searching
    • 7.6 Sorting
    • 7.7 Ethical Issues Around Data Collection
  • Unit 8 2D Array
    • 8.1 2D Arrays
    • 8.2 Traversing 2D Arrays
  • Unit 9 Inheritance
    • 9.1 Creating Superclasses and Subclasses
    • 9.2 Writing Constructors for Subclasses
    • 9.3 Overriding Methods
    • 9.4 super Keyword
    • 9.5 Creating References Using Inheritance Hierarchies
    • 9.6 Polymorphism
    • 9.7 Object Superclass
  • Unit 10 Recursion
    • 10.1 Recursion
    • 10.2 Recursive Searching and Sorting
  • Free Response Questions
    • 2021
    • 2022
    • 2023
    • 2024
  • Code
    • Week 1
    • Week 2
    • Week 3
    • Week 4
    • Week 5
    • Week 6
    • Week 7
    • Week 8
    • Week 9
    • Week 10
    • Week 11
    • Week 12
    • Week 13
    • Week 14
    • Week 15
    • Week 16
    • Week 17
    • Week 18
    • Week 19
    • Week 20
    • Week 21
    • Week 22
    • Week 23
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  • Learning Objectives
  • Essential Knowledge
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  1. Unit 2 Using Objects

2.2 Creating and Storing Objects (Instantiation)

Enduring Understanding

Some objects or concepts are so frequently represented that programmers can draw upon existing code that has already been tested, enabling them to write solutions more quickly and with a greater degree of confidence.

Learning Objectives

Identify, using its signature, the correct constructor being called.

Essential Knowledge

A signature consists of the constructor name and the parameter list.

The parameter list, in the header of a constructor, lists the types of the values that are passed and their variable names. These are often referred to as formal parameters.

A parameter is a value that is passed into a constructor. These are often referred to as actual parameters.

Constructors are said to be overloaded when there are multiple constructors with the same name but a different signature.

The actual parameters passed to a constructor must be compatible with the types identified in the formal parameter list.

Parameters are passed using call by value. Call by value initializes the formal parameters with copies of the actual parameters.

Learning Objective

For creating objects:

a. Create objects by calling constructors without parameters.

b. Create objects by calling constructors with parameters.

Essential Knowledge

Every object is created using the keyword new followed by a call to one of the class’s constructors.

A class contains constructors that are invoked to create objects. They have the same name as the class.

Existing classes and class libraries can be utilized as appropriate to create objects.

Parameters allow values to be passed to the constructor to establish the initial state of the object.

Enduring Understanding

To find specific solutions to generalizable problems, programmers include variables in their code so that the same algorithm runs using different input values.

Learning Objective

Define variables of the correct types to represent reference data.

Essential Knowledge

The keyword null is a special value used to indicate that a reference is not associated with any object.

The memory associated with a variable of a reference type holds an object reference value or, if there is no object, null. This value is the memory address of the referenced object.

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