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

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 (

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

Master-Slave Flip-Flop Operation

The working of a Master-Slave flip-flop involves two cascaded flip-flops: a master and a slave. The master is positive level-triggered, and the slave is negative level-triggered, ensuring the master responds before the slave.

When the clock pulse (CP) goes high (1), the slave is isolated, allowing the J and K inputs to affect the master's state. The slave flip-flop remains isolated until the CP goes low (0). When the CP transitions back to low, information is passed from the master flip-flop to the slave, and the output is obtained.

Let's examine the behavior based on J and K inputs:

• J=0, K=1: The high Q' output of the master goes to the K input of the slave. The negative transition of the clock forces the slave

C Programming Examples

Here are several C programming examples:

Vector Operations

#include <stdio.h>

void leVetor (int v [] , int tam );
int prodEscalar (int v1 [] , int v2 [] , int tam );

int main (void) {
    int v1 [ DIM ], int v2 [ DIM ];
    int i;
    int prod ;

    leVetor (v1 , DIM );
    leVetor (v2 , DIM );
    prod = prodEscalar (v1 , v2 , DIM );
    printf ("%d\n", prod );
    return 0;
}

void leVetor (int v [] , int tam ) {
    /* Completar */
}

int prodEscalar (int v1 [] , int v2 [] , int tam ) {
    /* Completar */
}

Random Number Generation

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

#define VEZES 10

int main (void) {
    int i , j , k;
    double r;

    srand ( time ( NULL )); /* inicializa

Heuristic Search Techniques Explained

Heuristic search techniques use intelligent estimations to find solutions efficiently. These methods help in decision-making by prioritizing the most promising paths.

1. Greedy Best-First Search (GBFS)

• Always chooses the next step that appears closest to the goal.
• Ignores the cost already traveled.

Example:

A person finding the exit of a maze by always taking the path that looks shortest.

⚠ Risk: May lead to dead ends.

2. A* Search Algorithm

• Balances actual cost and estimated cost to reach the goal.
• Ensures the shortest and most efficient path.

Example:

Google Maps finds the best route by considering both distance already covered and the remaining estimated distance.

✅ Optimal and efficient.

3. Hill Climbing Algorithm

• Moves