надо от обратного?
package com.javarush.task.task19.task1910;
/*
Пунктуация
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws IOException{
BufferedReader reader = new BufferedReader(
new InputStreamReader(System.in));
BufferedReader fileReader = new BufferedReader(new FileReader(reader.readLine()));
BufferedWriter fileWriter = new BufferedWriter(new FileWriter(reader.readLine()));
reader.close();
String str = "";
while(fileReader.ready()){
str = str + fileReader.readLine();
}
fileReader.close();
char[] ch = str.toCharArray();
for(char c : ch){
if ( (c >= 'a' && c <= 'z')||(c >= 'A' && c <= 'Z')||(c >= '0' && c <= '9')||(c >= 'а' && c <= 'я')||(c >= 'А' && c <= 'Я')||(c == 'ё')||(c == 'Ё') )
fileWriter.write(c);
}
fileWriter.close();
}
}