Practical No-1(b)

Aim: Write a program to implement Modified Caesar Cipher Substitution Technique.

Program:

import java.io.*;

import java.util.*;

import java.lang.String;

class ModifiedCaesar

{

public static void main(String[] args)throws Exception

{

try

{

int key;

String s;

Scanner in = new Scanner(System.in);

System.out.println("Enter a string to encrypt");

     

              s = in.nextLine();

              System.out.println("Enter a key");

              key=in.nextInt();

             

              char arr[]=s.toCharArray();

             

              String str=" ";

              for (int i=0;i < s.length(); i++)

              {

             

              int helper=s.charAt(i);

      helper=(helper+key);

      if (helper>'Z'||helper>'z') helper =(helper-26);

      if (helper<'A'||helper<'a') helper=(helper+26);

      str= str+(char)helper;

    }

            System.out.println("Cipher text: "+ str);

            }

            catch(Exception e)

            {

            System.out.println("Error"+e);

           

            }

            }

            }

Output:

Enter a String to encrypt : hello

Enter a Key : 4

Cipher text : limmp