Java第四章课后作业1

  import java.io.*;
  public class Exercise {
      public static void main(String[] args) throws IOException {
         
         BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));//输入
         String str = reader.readLine();
         
         char CharArray;
         for(int i =0;i<str.length();i++)//逐个输出字符
         {
            CharArray=(char)(str.charAt(i));
             if((CharArray>=65&&CharArray<=87)||(CharArray>=97&&CharArray<=119))
             {
                 CharArray += 3;
             }
             else
             {
                 CharArray = (char) (CharArray-23);
             }
             System.out.print(CharArray);
         }
     }
 }