Notes, summaries, assignments, exams, and problems for Computers

Lecture 2: Dynamic Dispatch and Interfaces

• Dynamic Dispatch: The process of selecting which implementation of a polymorphic operation to call at runtime.
• Interface: Calling a method that is not in the interface will cause a compilation error.

Lecture 3: N/A

Lecture 4: Method Contracts, Exceptions, and Unit Testing

• Method Contract: Should define pre/post conditions and exceptional behavior. The client is to blame if the precondition is not met, and the service is to blame if the postcondition is not met. Exceptional behavior specifies what the code will do if a precondition is violated.
• Exception: Runtime exception (unchecked) and IO exception (checked). The IO exception must be caught; otherwise, the code won't compile.
• Unit Test: Test boundary

What is a Neural Network?

A Neural Network is a component of Artificial Intelligence (AI) that mimics how the human brain works. It is used to process information, recognize patterns, and make decisions, similar to human cognition.

Core Structure and Function

• Neural networks are computer systems modeled on the structure of the human brain. They consist of layers of nodes (neurons).

Layers of a Neural Network

• Input Layer: Takes the input data.
• Hidden Layers: Process the data using mathematical operations.
• Output Layer: Gives the final result.

How Neural Networks Learn

Neural networks learn by identifying patterns in data through training.

How a Neural Network Works (Step-by-Step)

1. Input: Data is given to the network through the input layer.
2. Processing: Hidden

SnapMirror (SM)

SnapMirror (SM) requires a license. It operates at the volume or qtree level, is used for disaster recovery (DR) and replication, and requires both a source and destination filer.

Synchronous SnapMirror

Synchronous SM replicates from the source to the destination nearly at the same time data is written to the source (saved to NVRAM).

Command Notes

All SnapMirror commands must be run on the destination filer, except snapmirror status, which can be run on either the source or destination.

Configuration Steps

1. Enable SM on source & destination filer

   source-filer> options snapmirror.enable
   snapmirror.enable            on
   source-filer> options snapmirror.access
   snapmirror.access            legacy
   

2. SnapMirror access

   Ensure the destination

C++ Priority Queue Implementation

This document provides a C++ implementation of a priority queue using a heap data structure. The code includes the class definition, member functions, and supporting utilities.

Priority Queue Class Definition

#ifndef priority_queue_h_
#define priority_queue_h_

#include <iostream>
#include <vector>
#include <cassert>

template <class T>
class priority_queue {
private:
    std::vector<T> m_heap;

public:
    priority_queue() {}

    priority_queue(std::vector<T> const& values)
    {
        m_heap = values;
        for (int i = 0; i < m_heap.size(); i++){
            percolate_down(i);
            for (int j = i; j < m_heap.size(); j++){
                percolate_down(

This document provides practical SQL Data Definition Language (DDL) examples for creating and modifying database schemas across various common applications. Each section details the necessary tables and their relationships, offering a clear foundation for building robust relational databases.

Library Management System Database

The following SQL DDL statements define the core tables for a library management system, enabling the tracking of books, members, and loan transactions.

Table Creation

CREATE TABLE Books (
    BookID INT PRIMARY KEY,
    Title VARCHAR(100) NOT NULL,
    Author VARCHAR(100) NOT NULL,
    ISBN VARCHAR(20) UNIQUE,
    PublishedYear INT CHECK (PublishedYear >= 1500 AND PublishedYear <= 2025)
);

CREATE TABLE Members (

1. Boot Sector Virus

• It is a type of virus which infects the master boot record (portion of the hard disk which helps to load the OS) or hard disks.
• The infected code runs when the system is booted from an infected disk.
• They infect at a BIOS level (BIOS checks hardware and loads the OS).
• They use DOS commands (text-based commands used to perform tasks such as file management, disk management, and running programs) to spread to other floppy disks. Since floppy disks are rarely used now, the propagation of boot sector viruses has almost ended.
• With the boot-sector safeguards in operating systems, boot-sector viruses can no longer infect computers.
• This virus can infect a computer only during boot-up. Once the system has started and the OS is running,

Compile and Go Loaders

In this type of loader, the linker and loader instructions are read line by line, their machine code is obtained, and it is directly placed in the main memory at some known address. This means the assembler runs in one part of memory, and the assembled machine instructions and data are directly put into their assigned memory locations. After completion of the assembly process, the loader contains the instruction using which the location counter is set to the start of the newly assembled program. A typical example is WATFOR-77, a FORTRAN compiler which uses such a "load-and-go" scheme. This loading scheme is also called "assemble-and-go".

Advantages

• Simplicity
• Quick Testing
• No Separate Linking
• Immediate Feedback
• Low Resource

What is an Exception?

Answer: An exception in Python is an error that occurs during program execution, disrupting the normal flow of instructions. Instead of crashing, the program can "catch" the exception and handle it gracefully using try and except blocks. Common exceptions include ZeroDivisionError, IndexError, and FileNotFoundError. You can also define custom exceptions. The finally block can be used for cleanup actions, ensuring certain code runs regardless of whether an exception was raised.

Different Modes of Opening a File

Answer: Different Modes of Opening a File

1. Read Mode ('r')

• Purpose: Opens a file for reading.
• Behavior:
  • The file pointer is placed at the beginning of the file.
  • If the file does not exist, a FileNotFoundError is raised.

Definition of Software Engineering

Software engineering is the establishment and use of sound engineering principles in order to obtain software economically that is reliable and works efficiently on real machines.

Need for Software Requirements Specification (SRS)

The Software Requirements Specification (SRS) is necessary because it provides:

• A detailed overview of the software product, including its parameters and goals.
• A description of the project's target audience, user interface, and hardware and software requirements.
• A common understanding of how the client, development team, and audience perceive the product and its functionality.

Four Core Principles of Software Engineering

1. The Reason It All Exists (Value to Users)

• A software system exists