题解 | #字符串加解密#

import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        while(in.hasNext()){
            System.out.println(encode(in.nextLine()));
            System.out.println(decode(in.nextLine()));
        }
    }

    //加密函数
    private static String encode(String code){
        char[] t = code.toCharArray();    //将String对象转换为字符数组
        for(int i=0; i < t.length; i++){
            if(t[i]>='a' && t[i]<'z')
                t[i] = (char)(t[i] - 'a' + 'A' + 1);
            else if(t[i] == 'z')
                t[i] = 'A';
            else if(t[i]>='A' && t[i]<'Z')
                t[i] = (char)(t[i] - 'A' + 'a' + 1);
            else if(t[i] == 'Z')
                t[i] = 'a';
            else if(t[i]>='0' && t[i]<'9')
                t[i] = (char)(t[i]+1);
            else if(t[i] == '9')
                t[i] = '0';
        }
        return String.valueOf(t);
    }

    //解密函数
    private static String decode(String password){
        char[] t = password.toCharArray();
        for(int i=0; i < t.length; i++){
            if(t[i]>'a' && t[i]<='z')
                t[i] = (char)(t[i] - 'a' + 'A' - 1);
            else if(t[i] == 'a')
                t[i] = 'Z';
            else if(t[i]>'A' && t[i]<='Z')
                t[i] = (char)(t[i] - 'A' + 'a' - 1);
            else if(t[i] == 'A')
                t[i] = 'z';
            else if(t[i]>'0' && t[i]<='9')
                t[i] = (char)(t[i]-1);
            else if(t[i] == '0')
                t[i] = '9';
        }
        return String.valueOf(t);
    }
}