Notes, summaries, assignments, exams, and exercises for Computer science for Other courses

Validation Test Cases

Variables, Rules, Valid and Invalid Classes

Variable / Rule / Valid Class / Invalid Class

order_id / Datatype / ECV1: 32 hex string / ECNV1: not a string

order_id / Content: hexadecimal characters / ECV2: 32 hex string / ECNV2: 32 characters, non-hex

order_id / Size = 32 characters / ECV3: 32 hex string; BVV1: 32 hex string / ECNV3: more than 32 characters; ECNV4: less than 32 characters; BVNV1: 33 hex characters; BVNV2: 31 hex characters

new_order_type / Datatype / ECV4: valid value / ECNV5: datatype not string

new_order_type / Allowed values / ECV5: "REG"; ECV6: "PREM" / ECNV6: other value

- / Outputs / ECV7: valid phone number / ECNV7: Ex: InvalidOrder_idSize; ECNV8: Ex: order_idNotStr; ECNV9: Ex: ord_idNotHexVal; ECNV10: alreadySent;...

Java Swing and MySQL Registration Form Implementation

This project demonstrates how to create a desktop user registration form in Java using the Swing GUI toolkit and MySQL database connectivity (JDBC). It provides input handling, field validation, password confirmation, and persistent storage via prepared statements.

Complete Java Source Code

package javamysqlconnect;

import javax.swing.*;
import java.awt.event.*;
import java.sql.*;

public class RegistrationForm {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(CreateRegistrationForm::new);
    }
}

class CreateRegistrationForm extends JFrame implements ActionListener {
    JTextField userIdInput, nameInput, addressInput, phoneInput, genderInput, emailInput;

Binary Tree Basics

• Root node: the node located at the top level of a binary tree, with no parent node.
• Leaf node: a node with no child nodes, whose two pointers both point to None.
• Edge: a line segment connecting two nodes, i.e., a node reference (pointer).
• The level of a node: increases from top to bottom; the root node is at level 1.
• The degree of a node: the number of its child nodes. In a binary tree, the degree is 0, 1, or 2.
• The height of a binary tree: the number of edges from the root node to the farthest leaf node.
• The depth of a node: the number of edges from the root node to that node.
• The height of a node: the number of edges from the farthest leaf node to that node.

Example of inserting and deleting a node:

TreeNode P = new TreeNode(0);
/

LCD Interfacing with 8051

#include <reg51.h>

sbit rs = P2^0;
sbit rw = P2^1;
sbit e = P2^2;

void msdelay(unsigned int time) {
    unsigned int i, j;
    for(i = 0; i < time; i++)
        for(j = 0; j < 1275; j++);
}

void lcd_cmd(unsigned char command) {
    P1 = command;
    rs = 0;
    rw = 0;
    e = 1;
    msdelay(1);
    e = 0;
}

void lcd_init() {
    lcd_cmd(0x38); // 2 lines and 5x7 matrix
    msdelay(10);
    lcd_cmd(0x0F);
    msdelay(10);
    lcd_cmd(0x01);
    msdelay(10);
    lcd_cmd(0x80);
    msdelay(10);
}

void lcd_data(unsigned char disp_data) {
    P1 = disp_data;
    rs = 1;
    rw = 0;
    e = 1;
    msdelay(1);
    e = 0;
}

void main() {
    unsigned char a[4] = "KTU";
    int l = 0;
    lcd_init();
    while(

Java Interview Questions on OOP Concepts

• What is the difference between loose coupling and tight coupling?

İki nesne birbirine çok fazla bağlıysa, yani biri değiştiğinde diğerini de değiştirmek gerekiyorsa tight coupling; değiştirmek gerekmiyorsa, birbirinden bağımsızsa loose coupling deriz.

• Cohesion and coupling

Cohesion is defined as the degree of relationship between elements of the same module. Coupling is defined as the degree of interdependence between the modules.

• SOLID
• Single Responsibility Principle (Tek servis tek iş yapar)
• Open/Closed Principle (Yeni class için açık, modify için kapalı bir kod)
• Liskov Substitution Principle (Parent ve child classlar yer değiştirdiğinde aynı özellikleri gösterecek şekilde hiyerarşi

ConjuntoDatos Class in Java

public ConjuntoDatos(File archivoTexto, String separador, Locale locale) throws Exception {
    this.archivoTexto = archivoTexto;
    this.separador = separador;
    this.locale = locale;
    cabecera = cabecera(this.archivoTexto);
    numeroLineas = numLineas(this.archivoTexto);
    numeroColumnas = numColumnas(this.archivoTexto);
    datos = leerDatos(this.archivoTexto, numeroLineas, numeroColumnas);
}

Reading the Header

private List cabecera(File archivoTexto) throws Exception {
    cabecera = new ArrayList();
    Scanner fichero = new Scanner(archivoTexto);
    String primeraLinea = fichero.nextLine();
    Scanner scLinea = new Scanner(primeraLinea);
    scLinea.useDelimiter(separador)

Entrada y salida en Java: catálogo de productos

A continuación se muestran las clases EntradaSalida, Producto, Catalogo y principal, que permiten introducir productos por teclado, mostrar el catálogo y guardarlo o leerlo desde un fichero.

Clase EntradaSalida

Esta clase centraliza la lectura de datos por teclado y el acceso a ficheros.

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Scanner;

public class EntradaSalida {
    private static Scanner teclado = new Scanner(System.in);

    public static String leeString(String mensaje) {
        System.out.println(mensaje);
        return teclado.nextLine();
    }

    public static float leeFloat(String mensaje)

Pascal Programs

Program 1: pais

program pais;
var
  ano: integer;
  x, y: real;
begin
  writeln('ano');
  readln(ano);
  writeln('Y');
  readln(y);
  x := y * 2;
  while (y < x) do
  begin
    x := x * 1.03;
    y := y * 1.06;
    ano := ano + 1;
  end;
  writeln('X', x:8:2);
  writeln('Y', y:8:2);
  writeln('ano', ano);
end.

Program 2: caradepau

program caradepau;
var
  sexo, resp: char;
  id, numEnt, numS, numN, mascN, femS, masc23S, fem23N, col, lin: integer;
  percS, precN: real;
begin
  lin := 2;
  col := 3;
  numEnt := 0;
  numN := 0;
  numS := 0;
  femS := 0;
  mascN := 0;
  masc23S := 0;
  fem23N := 0;
  write(' IDADE SEXO RESP ');
  gotoxy(col, lin);
  readln(id);
  while (id > 0) do
  begin
    gotoxy(col+7, lin);
    readln(sexo)

O código a seguir apresenta um sistema de passagens desenvolvido em Java, utilizando herança e polimorfismo. A classe abstrata Passagem reúne os atributos comuns, enquanto as classes PassagemNacional e PassagemInternacional especializam o cálculo do valor total.

Classe abstrata Passagem

A classe Passagem define os atributos básicos de uma passagem, como número, nome do passageiro, origem, destino, quantidade, valor da passagem, tarifa, serviço de bordo e seu valor.

public abstract class Passagem {
private int numero;
private String nome;
private String origem;
private String destino;
private int quantidade;
private float valorPassagem;
private float tarifa;
private boolean servicoBordo;
private float valorServicoBordo;

public Passagem(

Consultas SQL básicas con funciones de agregación

Función en PL/SQL: multiplicación

Procedimiento en PL/SQL: cálculo de fechas