Untitled

import java.io.*;

class CaesarDemo {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter any String: ");
        String str = br.readLine();

        String e = encrypt(str, 3);
        System.out.println("Encrypted String is: " + e);

        String d = decrypt(e, 3);
        System.out.println("Decrypted String is: " + d);
    }

    static String encrypt(String str, int key) {
        String cipher = "";
        for (int i = 0; i < str.length(); i++) {
            int c = str.charAt(i);
            c = c + (key % 26);
            cipher += (char) c;
        }
        return cipher;
    }

    static String decrypt(String str, int key) {
        String plain = "";
        for (int i = 0; i < str.length(); i++) {
            int c = str.charAt(i);
            c = c - (key % 26);
            plain += (char) c;
        }
        return plain;
    }
}