I am currently writing a Caesar Cipher program in C# for my assignment and I am having a problem.
I am approaching this task using an array where I store the whole alphabet and I declare a shift variable which is defined by character index in the array - the iteration of a for loop. The shift calculation is done in a foreach loop, that fetches a character from a string that is read from a text file. Foreach loop is contained within a for loop that iterates to output every possible shift.
However, the problem is that when I try to access the character in an array by a value of my shift variable, the program doesn't seem to access the character I want, it just outputs the same character as in the original string.
This is the code for the program:
using System;
using System.IO;
public class caesar_shift
{
public static void Main()
{
string file = @"C:Userserasss2DesktopProgramming and Data StructurescaesarShiftEncodedText.txt"; //String variable that stores a file location
string encrypted_text = File.ReadAllText(file); //String variable that contains the text from a file. To get the text, the method in a class SystemIO is ran to read the text. It expects a parameter, which is a file directory.
string decoded_text = " ";
int shift = 0;
char character = '0';
char[] alphabet = new char[26]{'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
Console.WriteLine("The encrypted text is
{0}", encrypted_text); //Display the encrypted text
for(int i = 0; i < alphabet.Length; i++) //Start a loop which will display 25 different candidates of decipher
{
foreach(char c in encrypted_text)
{
character = c;
if(character == ''' || character == ' ')
continue;
shift = Array.IndexOf(alphabet, character) - i; //Define a shift which is the index of a character in an alphabet array, take away the itteration of this loop. Store the result in a variable
if(shift <= 0)
shift = shift + 26;
if(shift >= 26)
shift = shift - 26;
character = alphabet[shift]; //Set the character to a shifted letter by accessing the array element of a value shift
Console.WriteLine(character);
decoded_text = decoded_text + character;
}
Console.WriteLine("
Shift {0}
{1}",i + 1, decoded_text);
}
}
}
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