Chapter 9, Problem 8PP

Program Plan Intro

Form design:

• Open Microsoft Visual Studio 2010.
• Select C# and click Windows Forms Application.
• Name the project as Encryption.
• Store the file in desire location.
• The created project is now display with a form in the name of Form1.
• Select the Form1 and add the necessary components.
• In property window, change the Form name and add changes for Form elements properties.
• Click the File menu->Save All.

View of the form design in the IDE:

The form control properties in the properties window are as follows:

Object	Property	Setting
Form1	Text	Encryption
goButton	Text	Encrypt File

• Add a button control to start the encryption process.

Form design:

• Open Microsoft Visual Studio 2010.
• Select C# and click Windows Forms Application.
• Name the project as Decryption.
• Store the file in desire location.
• The created project is now display with a form in the name of Form1.
• Select the Form1 and add the necessary components.
• In property window, change the Form name and add changes for Form elements properties.
• Click the File menu->Save All.

View of the form design in the IDE:

The form control properties in the properties window are as follows:

Object	Property	Setting
Form1	Text	Decryption
goButton	Text	Decrypt File
outputListBox	Items	(Empty)

• Add a button control to start the decryption process.
• Add a list box control to show the decrypted text.

Explanation of Solution

• Add the following code in Form1.cs.

//Importing the required header files

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.IO;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace Decryption

{

    public partial class Form1 : Form

    {

        // Declaring the dictionary to store characters and keys

        Dictionary<char, char> codes = new Dictionary<char,

        char>()

        {

           { 'A', '!' }, { 'a', 'q' }, { 'B', 'a' }, { 'b', 'z'

           }, { 'C', '@' }, { 'c', 'w' },{ 'D', 's' }, { 'd',

           'x' }, { 'E', '#' }, { 'e', 'c' }, { 'F', 'd' }, {

           'f', 'e' }, { 'G', '$' }, { 'g', 'r' }, { 'H', 'f'

           }, { 'h', 'v' }, { 'I', '%' }, { 'i', 't' }, { 'J',

           'g' }, { 'j', 'b' }, { 'K', '^' }, { 'k', 'y' }, {

           'L', 'h' }, { 'l', 'n' }, { 'M', '&' }, { 'm', 'u'

           }, { 'N', 'j' }, { 'n', 'm' }, { 'O', '*' }, { 'o',

           'i' },{ 'P', 'k' }, { 'p', '<' }, { 'Q', '(' }, {

           'q', 'o' }, { 'R', 'l' }, { 'r', '>' },{ 'S', ')' },

           { 's', 'p' }, { 'T', ':' }, { 't', '/' }, { 'U', '-'

           }, { 'u', '[' },{ 'V', '"' }, { 'v', '+' }, { 'W',

           ']' }, { 'w', '\\'}, { 'X', ';' }, { 'x', '.'},{ 'Y',

           ',' }, { 'y', '|' }, { 'Z', '=' }, { 'z', '_' }, { '

           ', '~' }, { ',', 'X' },{ '.', '2' }, { '?', '3' }, {

           '\n', '\t' }, {'\t', ' ' }};

        public Form1()

        {

            InitializeComponent();

        }

        //GetInputFileName() opens the OpenFileDialog to select 

        the file and returns the file name or returns an empty

        string if cancel button is clicked

        private string GetInputFileName()

        {

            string infileName = "";

            if (openFileDialog.ShowDialog() == DialogResult.OK)

            {

                infileName = openFileDialog.FileName;

            }

            return infileName;

        }

        //Defining the DecryptFile() that accepts input file

        from the user

        private void DecryptFile(string infileName)

        {

            try

            {

                // Opening the file

                StreamReader infile =

                 File.OpenText(infileName);

                // Encrypting the input file

                while (!infile.EndOfStream)

                {

                    // Reading the lines  from the input file...