题解 | #简单密码#

1. String.toCharArray()将字符串转为字符数组
2. A的ASCII码是65，a的ASCII码是97。
   同样的字母，小写字母的ASCII码值比大写字母的ASCII码值大32，小写字母ASCII = 大写字母ASCII + 32 。
3. 增强型遍历for (char c : ch)

ASCII码记不住的版本：

import java.util.*;
import java.lang.*;

public class Main {
    public static void main (String[] args) {

        Scanner sc = new Scanner(System.in);

        String str = sc.next();
        char[] ch = str.toCharArray();

        for (int i = 0; i <ch.length; i++) {
            if (ch[i] >= 'a' && ch[i] <= 'c') {
                ch[i] = '2';
            } else if (ch[i]>='d' && ch[i] <= 'f') {
                ch[i] = '3';
            } else if (ch[i]>='g' && ch[i] <= 'i') {
                ch[i] = '4';
            } else if (ch[i]>='j' && ch[i] <= 'l') {
                ch[i] = '5';
            }else if (ch[i]>='m' && ch[i] <= 'o') {
                ch[i] = '6';
            }else if (ch[i]>='p' && ch[i] <= 's') {
                ch[i] = '7';
            }else if (ch[i]>='t' && ch[i] <= 'v') {
                ch[i] = '8';
            }else if (ch[i]>='w' &&ch[i] <= 'z') {
                ch[i] = '9';
            }

            if (ch[i]>='A' && ch[i]<='Z') {
                if (ch[i] != 'Z') {
                    ch[i]++;
                    ch[i] += 32;
                } else {
                    ch[i] = 'A';
                    ch[i] += 32;
                }
            }

        }

        for (char c : ch) {
            System.out.print(c);
        }
    }
}