EncryptGameTest.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */

import java.util.Scanner;
import java.util.Random;

/**
 *
 * @author cjyen
 */
public class Assignment1 {
    public static void main(String[] args)
    {
        Scanner keyboard = new Scanner(System.in);
        Random rand = new Random();
        
        String encode;
        char name;
        int Change = 0;
        int option = 0;
        String pText = " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String cText = "qwermnblkjhzxcpoiuasdf ytgvQWERMNBLKJHZXCPOIUASDFYTGV";
        //substitute letter into a temporary arrays
        char Letters[] = new char[53];
        for(int p = 52; p >= 0; p--)
        {
            Letters[p] = cText.charAt(p);
        }
        
        //randomly exchange the letters
        //reason why dont use i++ because at the end the numbers will not be exchanged much.
        for(int i =52; i>=0; i--)
        {
            int j =rand.nextInt(0,2); //when i =52, let j be the random numbers from 0~52
            char temp = Letters[i];
            Letters[i] = Letters[j];
            Letters[j] = temp;
        }
        //change the cText to the new cText, because Letters is a char element, this line is also to change it to string element
        cText = new String(Letters);
        //menu select
        while(option != 3)
        {
            boolean option1 = false;
            String randomtext = "";
            String reverse = "";
            String finaltext = "";
            String even = "",odd = "";
            
            System.out.println("Menu:");
            System.out.println("[1] Encrypt");
            System.out.println("[2] Decrypt");
            System.out.println("[3] Exist");
            option = keyboard.nextInt();
            //https://stackoverflow.com/questions/13102045/scanner-is-skipping-nextline-after-using-next-or-nextfoo
            
            if(option == 1)
            {
                System.out.println("\nSystem Encrypt:");
                option1 = true;
            }
            else if(option == 2)
            {
                System.out.println("\nSystem Decrypt:");
            }
            else if(option == 3)
            {
                System.out.println("\nThanks for playing");
            }
            else
            {
                System.out.println("Please enter option again!!!");
            }
            
            if(option !=3)
            {
                System.out.println("\nPlease enter the text you want");
                encode = keyboard.nextLine();
            }
            else
            {
                encode = "";
            }
            
            if(option1)
            {
                //encrypt
                for(int i = 0; i<encode.length();i++)
                {
                    Change = pText.indexOf(encode.charAt(i));
                    name = cText.charAt(Change);


                    randomtext = randomtext + name;
                }
            }
            else
            {
                //decrypt
                for(int i = 0; i<encode.length();i++)
                {
                    Change = cText.indexOf(encode.charAt(i));
                    name = pText.charAt(Change);


                    randomtext = randomtext + name;
                }
            }
            //reverse section
            for(int i = 1; i<=randomtext.length();i++)
            {
                reverse = reverse + randomtext.charAt(randomtext.length()-i);
            }
            //odd number or even rearrange
            for(int i = 0; i<randomtext.length();i++)
            {
                if(i%2 == 0)
                {
                    even = even + randomtext.charAt(i);
                }
                else
                {
                    odd = odd + randomtext.charAt(i);
                }
            }
            finaltext= even + odd;  
            //outprint
            if(option != 3)
            {
                System.out.printf("\nEncrypt:\t\t%s\n", randomtext);
                System.out.printf("Reverse:\t\t%s\n", reverse);
                System.out.printf("Encrypted(odd):\t%s\n\n", finaltext);
            }
        }
    }
}