answer.java

import java.util.*;

//Define the class decryption.

public class decryption

{

//Define the main() method.

public static void main(String[] args)

{

//Declare the required variables.

String encryptedText;

String decryptedText="";

Scanner s = new Scanner(System.in);

//Prompt the user for the input.

System.out.println("Enter the message"+

" to be decrypted");

//Store the encrypted message in

//the string object encryptedText.

encryptedText = s.nextLine();

//Print the encrypted string on the screen.

System.out.println("Encrypted Message "

+encryptedText);

//Run the loop till the value of the variable

//key is greater than 99.

for (int key = 1; key < 100; key++)

{

//Traverse the encrypted string character

//by character.

for (int index = 0; index <

encryptedText.length();index++)

{

//Get the character at the current

//position of the encrypted message.

char encryptedchar =

encryptedText.charAt(index);

char decryptedChar;

//Check if encrypted key is greater

//than 126.

if(((int)encryptedchar+127-32)>126)

{

//Get the decrypted character.

decryptedChar=(char)

((encryptedchar-key+127)-32);

}

//Else if if (original character+key)

//is less than 126.

else

{

//Get the decrypted character.

decryptedChar=(char)

(encryptedchar-key);

}

//Append the current decrypted

//character to the decryptedText

//string object.

decryptedText+=decryptedChar;

}

//Print the decrypted message

//with the current key.

System.out.println

("Decrypted Message at key "+key+" is "

+decryptedText);

//Reset the string decryptedText

//object.

decryptedText="";