Practice Exercises C# Sharp - Learn to program with performing exercises C# Sharp

Practice Exercises C# Sharp

Learn to program with performing exercises C# Sharp

Text file reader - Practice Exercises C# Sharp
Practice Exercises C# Sharp4,85320940

ArrayList - Text file reader - Practice Exercises C# Sharp


Lesson 11:

Dynamic memory management


Exercise 11.8:

ArrayList - Text file reader


Objetive:

Deliver here your basic text file reader.

This text file reader always shows 21 lines of the text file, and the user could use up key to show the previous line, down key to show the next line, and ESC key to exit.

Hints:
The text file reader should have 3 methods:
- ReadFile (Read the text file and store it in memory)
- ShowMenu (Clear the console and prepare the top line and the bottom line [raw 23] of the console, changing colours using Console.BackgroundColor, Console.ForegroundColor, ConsoleColor and Console.SetCursorPosition(column, raw). Once the menu is prepared, remember to set the cursor in the second raw).
- ShowFrom (write 21 lines, considering the position of the first line to write)
The logic of the main program should be like: ShowMenu, ShowFrom, ReadKey, ShowMenu, ShowFrom, ReadKey....


Source Code:


using System;
using System.IO;
using System.Collections;
namespace LectorTexto
{
    class Program
    {
        static ArrayList lista = new ArrayList();
        static bool fin;
        static int lineaDesde = 0, lineaHasta = 21;

        static void Main(string[] args)
        {
            Console.Write("Introduce nombre archivo: ");
            string nombreArchivo = Console.ReadLine();

            LeerFichero(nombreArchivo);

            do
            {
                MostrarMenu();
                EscribirLineas(lineaDesde, lineaHasta);
                LeerTecla();
            }
            while (!fin);

        }
        static void LeerTecla()
        {
            ConsoleKeyInfo cki;
            cki = Console.ReadKey();

            if (cki.Key == ConsoleKey.Escape)
            {
                fin = true;
            }
            else if (cki.Key == ConsoleKey.UpArrow)
            {
                if (lineaDesde > 0)
                {
                    lineaDesde--;
                    lineaHasta--;
                }
            }
            else if (cki.Key == ConsoleKey.DownArrow)
            {
                if (lineaHasta < lista.Count)
                {
                    lineaDesde++;
                    lineaHasta++;
                }
            }
            else if (cki.Key == ConsoleKey.PageUp)
            {
                if ((lineaHasta + 21) < lista.Count)
                {
                    lineaDesde += 21;
                    lineaHasta += 21;
                }
                else
                {
                    lineaDesde += lista.Count - lineaHasta;
                    lineaHasta += lista.Count - lineaHasta;
                }
            }
            else if (cki.Key == ConsoleKey.PageDown)
            {
                if ((lineaDesde - 21) > 0)
                {
                    lineaDesde -= 21;
                    lineaHasta -= 21;
                }
                else
                {
                    lineaHasta = lineaDesde + (21 - lineaDesde);
                    lineaDesde = 0;
                }
            }
        }

        static void EscribirLineas(int desde, int hasta)
        {
            for (int i = desde; i < hasta; i++)
            {
                Console.WriteLine(lista[i]);
            }
        }

        static void MostrarMenu()
        {
            Console.Clear();
            Console.BackgroundColor = ConsoleColor.Cyan;
            Console.ForegroundColor = ConsoleColor.Black;
            Console.WriteLine("    ==> Lector .txt --- Version 1.0");

            Console.SetCursorPosition(0, 23);
            Console.BackgroundColor = ConsoleColor.Cyan;
            Console.ForegroundColor = ConsoleColor.Black;
            Console.WriteLine("Pulse ESC para salir, fecha arriba y abajo para mover");

            Console.SetCursorPosition(0, 1);
            Console.BackgroundColor = ConsoleColor.Black;
            Console.ForegroundColor = ConsoleColor.White;
        }

        static void LeerFichero(string nombreArchivo)
        {
            if (!File.Exists(nombreArchivo))
            {
                Console.WriteLine("El fichero de texto no existe");
            }
            else
            {
                try
                {
                    StreamReader archivoTexto = File.OpenText(nombreArchivo);
                    string line;

                    do
                    {
                        line = archivoTexto.ReadLine();
                        if (line != null)
                            lista.Add(line);
                    }
                    while (line != null);

                    archivoTexto.Close();
                }
                catch (Exception e)
                {
                    Console.WriteLine("Error, " + e.Message);
                }
            }
        }
    }
}
Exercisey 11.8

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