算法提高 9-2 文本加密

import java.util.Scanner;

public class Main {

    public static String EncryptChar(String str){
        StringBuffer result = new StringBuffer();
        for ( int i = 0 ; i < str.length() ; i++){
            char a = str.charAt(i);
            if (a >= 'A' && a < 'Z'){
                a = (char) (a + 1);
                result.append(a);
            }else if (a == 'Z'){
                a = 'a';
                result.append(a);
            }else if (a >= 'a' && a < 'z'){
                a = (char) (a + 1);
                result.append(a);
            }else if(a == 'z'){
                a = 'A';
                result.append(a);
            }else{
                result.append(a);
            }
        }
        return result.toString();
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        String word = in.next();
        String result = EncryptChar(word);
        System.out.println(result);
        in.close();
    }

}