AP Computer Science A: Java Review & Free-Response Questions
AP COMPUTER SCIENCE 2020 CHEAT SHEET – WILLIAM KONG
1) Strings
A string is a line of text, an object in Java, defined by the String class.
String concatenation – Use the + operator to add multiple strings or numbers.
A string is an array of characters.
Methods of the String Class
int length()– Returns the length of the string.String substring(int from, int to)– Returns a substring from the specified starting index (inclusive) to the ending index (exclusive).String substring(int from)– Returns a substring
Understanding Data Units, Python, R, Excel, and SQL
Understanding Data Units
Common Data Units
Bit (b): The smallest unit of data storage, representing a binary digit (0 or 1).
Byte (B): A group of 8 bits, typically representing a single character.
Kilobyte (KB): 1,024 bytes.
Megabyte (MB): 1,024 KB.
Gigabyte (GB): 1,024 MB.
Terabyte (TB): 1,024 GB.
Petabyte (PB): 1,024 TB.
Exabyte (EB): 1,024 PB.
Zettabyte (ZB): 1,024 EB.
Yottabyte (YB): 1,024 ZB.
Python Basics
Key Concepts
- Python is case-sensitive.
- Indentation is crucial for code blocks.
- The
print()function outputs
Understanding Computer Networks: Communication Structures, Protocols, and Design
Communication Structures
Key Elements:
- Naming and Name Resolution: Identifies processes with host and process IDs, utilizing DNS.
- Routing Strategies:
- Fixed Routing: Predefined path from source to destination.
- Virtual Circuit: Fixed path for a single session.
- Dynamic Routing: Path determined at the time of message sending.
- Connection Strategies:
- Circuit Switching: Dedicated physical link for the duration of communication (e.g., mobile phones).
- Message Switching: Temporary link for a single message transfer
Database Normalization and Transaction Management: A Comprehensive Guide
Understanding Database Normalization
Goals of Normalization
Normalization is a crucial process in database design aimed at organizing data efficiently and minimizing redundancy. Its primary goals include:
- Minimizing Data Redundancy: Eliminating duplicate data to save storage space and ensure consistency.
- Ensuring Data Integrity: Maintaining data accuracy and consistency through logical organization and redundancy reduction.
Advantages of Normalization
Implementing normalization offers several benefits,
Read MoreIP Routing, Datagram Routing, and Transport Layer
K- IP Routing & Transp:1-Datagram Routing:
Decision-making process on where to forward datag. Any device making such decision is called a router. Routing can be direct (host part of the LAN) or indirect (other cases). Routers form a cooperative interconnected structure. Datagrams pass from router to router until they reach a router capable of delivering directly (locally) to the destination.
Table Driven Routing:
Every router maintains a routing table with entries in the form of pairs-(N, G),
Read MoreSoftware Development Life Cycle Models: A Comprehensive Guide
Software Development Life Cycle Models
Activity-Centered vs. Entity-Centered Views
Activity-centered models focus on the activities involved in software development, while entity-centered models emphasize the work products created during these activities.
The activity-centered view helps participants understand how work products are created, while the entity-centered view focuses on the content and structure of the work products.
IEEE 1074 Standard
The IEEE 1074 standard provides a common framework for
Read More