public string DecryptText(string inputstr)
{
EncryptDecryptText decrypttext = new EncryptDecryptText();
var formattedstring = decrypttext.FormattedString(inputstr);
formattedstring = formattedstring.Substring(0, formattedstring.IndexOf("numsp"));
var indexes = inputstr.Substring(inputstr.IndexOf("numsp") + 5);
string[] formattedIndex = indexes.Split(' ');
int inputLength = formattedstring.Length;
var sqrRoot = Math.Sqrt(inputLength);
int noofRows = Convert.ToInt16(Math.Floor(sqrRoot));
int noofColumns = noofRows;
while (noofRows * noofColumns < inputLength) // to calculate no of rows and no of coulumns
{
noofColumns = noofColumns + 1;
}
if (noofRows * noofColumns - inputLength != 0)
{ // to add dummy input if the string is not in the exact matrix 3*3 or 4*4 or 5*5
var insertIndex = noofRows * (noofColumns - (noofRows * noofColumns - inputLength - 1)) - 1;
for (int extrainput = inputLength; extrainput < noofRows * noofColumns; extrainput++)
{
formattedstring = formattedstring.Insert(insertIndex, "-");
insertIndex += noofRows;
}
}
var decryptedmsg = "";
int i = 0, j = 0;
int count = 1, formattedindexcount = 1;
while (j < noofRows)
{
i = j;
while (i < formattedstring.Length)
{
if (formattedstring[i] != '-')
{
decryptedmsg = decryptedmsg + formattedstring[i];
}
i = i + noofRows;
count++;
if (formattedindexcount <= formattedIndex.Length - 1 && count == Convert.ToInt16(formattedIndex[formattedindexcount]))
{
decryptedmsg = decryptedmsg + " ";
formattedindexcount++;
}
}
j++;
}
return(decryptedmsg);
}
public string EncryptText(string inputstr)
{
var encryptedmsg = "";
EncryptDecryptText encrypttext = new EncryptDecryptText();
var formattedInput = encrypttext.FormattedString(inputstr);// to remove spaces for the text given
int indexcount = 1;
List <int> formattedIndex = new List <int>();
var inputlength = formattedInput.Length;
foreach (char c in inputstr) // To take the indexs for the spaces
{
if (c == ' ')
{
formattedIndex.Add(indexcount);
}
else
{
indexcount++;
}
}
if (inputlength > 81)
{
Console.WriteLine("The input should not exceed 81 characters ignoring spaces");
return("");
}
var sqrRoot = Math.Sqrt(inputlength);
int noofRows = Convert.ToInt16(Math.Floor(sqrRoot));
int noofColumns = noofRows;
while (noofRows * noofColumns < inputlength)
{
noofColumns = noofColumns + 1;
}
int i = 0, j = 0;
while (j < noofColumns)
{
i = j;
int count = 0;
while (i < inputlength)
{
encryptedmsg = encryptedmsg + formattedInput[i];
i = i + noofColumns;
count++;
}
j++;
encryptedmsg = encryptedmsg + " ";
}
encryptedmsg += "numsp " + String.Join(" ", formattedIndex);
return(encryptedmsg); // to disaply the encryted msg
}
static void Main(string[] args)
{
try
{
Console.WriteLine("please enter the text to be encrypted");
string inputstr = Console.ReadLine(); // Taking the Input from user to encrypt
EncryptDecryptText p = new EncryptDecryptText();
var encryptedmsg = p.EncryptText(inputstr);
Console.WriteLine("Encrypted text is :{0}", encryptedmsg);
Console.WriteLine("please enter the encrypted text to be decrypted");
var decrypttext = Console.ReadLine(); // Taking the encrypted Input from user to decrypt
var decryptedmsg = p.DecryptText(decrypttext);
Console.WriteLine("Decrypted text is :{0}", decryptedmsg);
}
catch (Exception ex)
{
Console.WriteLine("please enter proper input");
Console.WriteLine("Exception caught: {0}", ex);
}
finally
{
Console.ReadLine();
}
}
