/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
	}
}

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import java.util.Scanner;

/**
 * 实验1：利用异或实现字符串加密和解密
 */
public class EncryptXOR {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        // 1. 输入明文和密钥
        System.out.print("请输入明文：");
        String plainText = sc.nextLine();

        System.out.print("请输入密钥字符：");
        char key = sc.nextLine().charAt(0);

        // 2. 加密
        String cipherText = encrypt(plainText, key);
        System.out.println("加密后的密文：" + cipherText);

        // 3. 解密（异或两次还原）
        String decryptText = encrypt(cipherText, key);
        System.out.println("解密后的明文：" + decryptText);

        sc.close();
    }

    // 加密/解密通用方法（异或一次加密，异或两次解密）
    public static String encrypt(String text, char key) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < text.length(); i++) {
            // 逐个字符异或
            char c = (char) (text.charAt(i) ^ key);
            sb.append(c);
        }
        return sb.toString();
    }
}