Computer Basics PDF

Computer Basics: -Hardware: physical, tangible parts (keyboard, monitor, disks, chips) -Software: programs and data -Both hardware and software are essential for computer function Main Components: -Central Processing Unit (CPU): executes program commands -Main Memory (RAM): primary sto...

Computer Basics: -Hardware: physical, tangible parts (keyboard, monitor, disks, chips) -Software: programs and data -Both hardware and software are essential for computer function Main Components: -Central Processing Unit (CPU): executes program commands -Main Memory (RAM): primary storage for active programs and data -Input/Output Devices: facilitate user interaction (monitor, keyboard, mouse) -Secondary Memory: long-term storage (hard disk, USB flash drive) Software Categories: -Operating System: controls machine activities, manages resources -Application Programs: specific software for various tasks Data Representation: -Analog: continuous, proportional representation -Digital: information broken into discrete pieces -Computers store all information digitally (numbers, text, graphics, audio, video) Computer Architecture: -Memory divided into cells with unique addresses -Information stored in bytes (usually 8 bits) -Storage capacity measured in KB, MB, GB, TB, PB Memory Types: -Main memory (RAM): volatile, direct access -Secondary memory: non-volatile, can be direct or sequential access -ROM: Read-Only Memory Central Processing Unit (CPU): -Follows fetch-decode-execute cycle -Components: Arithmetic/Logic Unit, Registers, Control Unit =Speed measured in gigahertz (GHz) Networks: -Two or more connected computers sharing data and resources -Each computer has a unique network address -File servers store shared programs and data Network Types: -Local Area Network (LAN): covers small distance/number of computers -Wide Area Network (WAN): connects multiple LANs, often over long distances Internet: -Global WAN using TCP/IP protocols -Each computer has unique IP address and domain name -Domain Name System (DNS) translates between IP addresses and domain names World Wide Web: -Accessed through browsers (e.g., Internet Explorer, Safari, Firefox) -Uses HTML for document structure -Resources located using URLs (Uniform Resource Locators) Lecture 2 Java Programming Language: -Created by Sun Microsystems in 1995 -Program structure: classes containing methods and statements -Java applications always have a main method Java Program Components: -Comments: explain program purpose and processing steps -Identifiers: "words" in a program (letters, digits, underscore, dollar sign) -Reserved words: predefined meanings in the language Program Development: -Writing code in a specific language -Translating code into executable form -Debugging errors Java Translation Process: Java source code compiled into bytecode Bytecode executed by Java Virtual Machine (JVM) Makes Java architecture-neutral Types of Errors: -Compile-time errors: syntax errors caught by compiler -Run-time errors: occur during program execution -Logical errors: program runs but produces incorrect results Object-Oriented Programming Concepts: -Objects: fundamental entities representing real-world concepts -Classes: blueprints for objects, defining state and behavior -Inheritance: deriving new classes from existing ones Indentation Rules: Definition: Indentation is the act of shifting text to the right by adding spaces or tabs at the beginning of lines. Syntactically Not Mandatory: From a purely syntactical perspective, indentation is not mandatory in most programming languages, including Java. Purpose: To visually represent the hierarchical structure of the code. To make it easier to identify which statements belong to which blocks of code. Best Practices: Following indentation rules is part of adhering to coding standards and best practices. Readability and Debugging: Proper indentation makes code structure clear, aiding in understanding and debugging. Language Specificity: In some languages like Python, indentation is part of the syntax and affects how the code runs. In Java, it's for readability only and doesn't affect execution. Common Indentation Units: Spaces: Usually 2, 4, or 8 spaces. Tabs: A single tab character. Consistency: Use consistent indentation throughout a file and project. Relation to Code Blocks: In most programming styles, each new block (defined by curly braces {} in Java) is indented one level. Not Just for Blocks: Indentation is also used for line continuation, aligning parameters in method calls, etc. Class Definition: The class body should be indented one level inside the class declaration. Method Definition: The method body should be indented one level inside the method declaration. Line Wrapping: If a line of code is too long and needs to be wrapped, indent the continued line. Typically, indent the wrapped part by 8 spaces or two levels. Comments: Inline comments should be indented to the same level as the code they describe. Block comments can start at the same indentation as the code they precede. Alignment: When breaking long method calls or declarations, align parameters under each other.