AP®︎ CS Principles Unit 3: Notes & Study Guide

Prepare for your quiz, test, or the AP exam with a comprehensive review on Unit 3 of AP CS Principles – Algorithms and Programming.

Exam weight: 30–35%
18 Topics

Unit 3: Algorithms and Programming

This unit focuses on designing algorithms and writing programs that use sequencing, selection, iteration, and abstraction to solve problems.

Begin with Topic 3.1: Variables and Assignments

To review Unit 3, go through each of the 18 topics below.

Everything you actually need to know for your Unit 3 test, pulled directly from the AP® Computer Science Principles curriculum.

Topic 3.1
~6 min
Review
Variables and Assignments
Variables and Assignments
  • What a Variable Is
  • Data Types Variables Can Represent
  • Assignment and the Assignment Operator
Review
Topic 3.2
~5 min
Review
Data Abstraction
Data Abstraction
  • What Lists and Strings Are
  • Creating and Assigning Lists in AP Pseudocode
  • Data Abstraction
Review
Topic 3.3
~6 min
Review
Mathematical Expressions
Mathematical Expressions
  • What an Algorithm Is
  • Sequencing and Code Statements
  • What Expressions Are
Review
Topic 3.4
~5 min
Review
Strings
Strings
  • What Strings Are
  • String Concatenation
  • Substrings and Indexing
Review
Topic 3.5
~6 min
Review
Boolean Expressions
Boolean Expressions
  • What Boolean Values Are
  • Relational Operators Compare Two Values
  • Logical Operators Combine or Modify Boolean Values
Review
Topic 3.6
~6 min
Review
Conditionals
Conditionals
  • What Selection Does in an Algorithm
  • Boolean Conditions Drive the Decision
  • The Two Forms of Conditional Statements
Review
Topic 3.7
~6 min
Review
Nested Conditionals
Nested Conditionals
  • What Nested Conditionals Are
  • The Structure of Nested Selection
  • How Nested Conditionals Execute
Review
Topic 3.8
~6 min
Review
Iteration
Iteration
  • What Iteration Is
  • REPEAT n TIMES
  • REPEAT UNTIL(condition)
Review
Topic 3.9
~6 min
Review
Developing Algorithms
Developing Algorithms
  • What It Means to Develop an Algorithm
  • Different Algorithms for the Same Problem
  • Equivalent Boolean Expressions and Conditionals
Review
Topic 3.10
~6 min
Review
Lists
Lists
  • What Lists Are and How Indexing Works
  • List Procedures on the Exam Reference Sheet
  • Traversing a List with Iteration
Review
Topic 3.11
~6 min
Review
Binary Search
Binary Search
  • What Binary Search Is
  • Requirements for Binary Search to Work
  • Binary Search vs Linear Search
Review
Topic 3.12
~6 min
Review
Calling Procedures
Calling Procedures
  • What a Procedure Is
  • Parameters, Arguments, and Return Values
  • How Procedure Calls Affect Program Flow
Review
Topic 3.13
~6 min
Review
Developing Procedures
Developing Procedures
  • What Procedural Abstraction Is
  • Modularity and Breaking Problems into Subproblems
  • Defining and Calling Procedures
Review
Topic 3.14
~6 min
Review
Libraries
Libraries
  • What Software Libraries Are
  • Where Existing Code Comes From
  • Application Programming Interfaces (APIs)
Review
Topic 3.15
~5 min
Review
Random Values
Random Values
  • What RANDOM(a, b) Does
  • Determining All Possible Results
  • Why Random Programs Produce Different Results
Review
Topic 3.16
~6 min
Review
Simulations
Simulations
  • What Simulations Are
  • How Simulations Represent Changing Phenomena
  • Why Simulations Are Useful
Review
Topic 3.17
~7 min
Review
Algorithmic Efficiency
Algorithmic Efficiency
  • What a Problem Is in Computing
  • What Algorithmic Efficiency Means
  • How to Estimate Efficiency
Review
Topic 3.18
~7 min
Review
Undecidable Problems
Undecidable Problems
  • What a Decidable Problem Is
  • What an Undecidable Problem Is
  • Some Instances Can Be Solved
Review

Notes

1 credit used · 5/5 remaining