Random Values
David Foster
9 min read
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Study Guide Overview
This AP Computer Science Principles study guide covers algorithms and program design (variables, data types, control structures, procedures, and random number generation), the internet and its global impact (internet basics, World Wide Web, and societal impacts), data and information (data representation, data storage, and data analysis), and cybersecurity and ethical computing (threats and protection, privacy, bias, intellectual property). The guide includes practice questions and key exam tips.
#AP Computer Science Principles: Ultimate Study Guide 🚀
Hey there, future AP Computer Science Principles master! This guide is designed to be your go-to resource for acing the exam. Let's break down the key concepts, one step at a time, with a focus on clarity and exam readiness. Let's get started!
#1. 💻 Algorithms and Program Design
#1.1 Variables and Data Types
- Variables: Think of these as containers that store information. They have names and hold values that can change during program execution.
- Data Types: The type of data a variable can hold (e.g., integer, string, boolean). Using the correct data type is crucial for accurate calculations and operations.
Understanding how to declare and use variables of different data types is fundamental to programming.
#1.2 Control Structures
- Sequence: Instructions are executed in order, one after the other.
- Selection (if, if-else): Code blocks are executed based on conditions. If the condition is true, the code runs; otherwise, it might not.
- Iteration (loops: for, while): Code blocks are repeated until a condition is met or for a specific number of times.
Pay close attention to loop conditions and how they affect the number of iterations. Off-by-one errors are common! 🧐
#1.3 Procedures (Functions)
- Procedures: Reusable blocks of code that perform specific tasks. They help in organizing and simplifying complex programs.
- Parameters: Inputs to procedures. They allow procedures to operate on different data.
- Return Values: The result a procedure sends back after it completes its task.
Think of procedures like mini-programs within your main program. They take input, do something, and might give you an output. 🛠️
#1.4 Random Number Generation
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Purpose: To introduce unpredictability and simulate real-world events in programs.
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Pseudocode:
RANDOM(a, b)generates a random integer betweenaandb, inclusive.
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Python Example:
python import random c = random.randint(a,b) ```
- Note: Each time you run a program with random numbers, you may get a different result.
Random numbers are essential for simulations and games. They make programs more dynamic and less predictable. 🎲
Practice Question
Multiple Choice
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What is the purpose of using a random number generator in a program? a) To make the program run faster b) To introduce unpredictability and simulate real-world events c) To ensure the program always produces the same output d) To make the code easier to read
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In pseudocode, what does
RANDOM(1, 10)return? a) A random integer greater than 1 and less than 10 b) A random integer between 1 and 10, inclusive c) A random float between 1 and 10 d) The average of 1 and 10
Free Response
Write a pseudocode program that simulates rolling a six-sided die 10 times and counts how many times a 6 is rolled. Output the count of 6s.
Scoring Rubric
| Points | Description |
|---|---|
| 1 | Correctly initializes a variable to store the count of 6s. ... |
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