这是一个我完全无法理解的家庭作业问题
它是一个非常简单的加密算法。您以一串字符作为字母表开始：
ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!, .
然后要求用户输入自己的字符串，map例如：
0987654321! .,POIUYTREWQASDFGHJKLMNBVCXZ
然后程序使用它来制作一个map并允许您输入被加密的文本。
例如MY NAME IS JOSEPH将被加密为.AX,0.6X2YX1PY6O3
这一切都很容易，但是他说这是一对一的映射，因此暗示如果我.AX,0.6X2YX1PY6O3重新进入程序，我就会退出MY NAME IS JOSEPH
这不会发生，因为.AX,0.6X2YX1PY6O3变成Z0QCDZQGAQFOALDH
该映射仅在您向后退时解密，但问题意味着程序每次都只是循环并运行一个算法。
即使有人会说我可能会很高兴，我有一页又一页的纸填满了可能的工作原理，但我什么也没想出来，唯一的解决方案是向后运行算法我不认为我们是允许这样做。
有任何想法吗？
编辑：
不幸的是我不能让它工作（使用轨道计算的想法）我做错了什么？
//import scanner class
import java.util.Scanner;
public class Encryption {
static Scanner inputString = new Scanner(System.in);
//define alphabet
private static String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!, .";
private static String map;
private static int[] encryptionMap = new int[40];//mapping int array
private static boolean exit = false;
private static boolean valid = true;
public static void main(String[] args) {
String encrypt, userInput;
userInput = new String();
System.out.println("This program takes a large reordered string");
System.out.println("and uses it to encrypt your data");
System.out.println("Please enter a mapping string of 40 length and the same characters as below but in different order:");
System.out.println(alpha);
//getMap();//don't get user input for map, for testing!
map=".ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!, ";//forced input for testing only!
do{
if (valid == true){
System.out.println("Enter Q to quit, otherwise enter a string:");
userInput = getInput();
if (userInput.charAt(0) != 'Q' ){//&& userInput.length()<2){
encrypt = encrypt(userInput);
for (int x=0; x<39; x++){//here I am trying to get the orbit computation going
encrypt = encrypt(encrypt);
}
System.out.println("You entered: "+userInput);
System.out.println("Encrypted Version: "+encrypt);
}else if (userInput.charAt(0) == 'Q'){//&& userInput.length()<2){
exit = true;
}
}
else if (valid == false){
System.out.println("Error, your string for mapping is incorrect");
valid = true;//reset condition to repeat
}
}while(exit == false);
System.out.println("Good bye");
}
static String encrypt(String userInput){
//use mapping array to encypt data
String encrypt;
StringBuffer tmp = new StringBuffer();
char current;
int alphaPosition;
int temp;
//run through the user string
for (int x=0; x<userInput.length(); x++){
//get character
current = userInput.charAt(x);
//get location of current character in alphabet
alphaPosition = alpha.indexOf(current);
//encryptionMap.charAt(alphaPosition)
tmp.append(map.charAt(alphaPosition));
}
encrypt = tmp.toString();
return(encrypt);
}
static void getMap(){
//get a mapping string and validate from the user
map = getInput();
//validate code
if (map.length() != 40){
valid = false;
}
else{
for (int x=0; x<40; x++){
if (map.indexOf(alpha.charAt(x)) == -1){
valid = false;
}
}
}
if (valid == true){
for (int x=0; x<40; x++){
int a = (int)(alpha.charAt(x));
int y = (int)( map.charAt(x));
//create encryption map
encryptionMap[x]=(a-y);
}
}
}
static String getInput(){
//get input(this repeats)
String input = inputString.nextLine();
input = input.toUpperCase();
if ("QUIT".equals(input) || "END".equals(input) || "NO".equals(input) || "N".equals(input)){
StringBuffer tmp = new StringBuffer();
tmp.append('Q');
input = tmp.toString();
}
return(input);
}
}