getCharAtIndexFromString

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class main {

    public static char getCharAtIndexFromString(ArrayList<String> strings, int index){
        //gaseste char-ul de la indexul dat
        //null daca indexul e mai mare decat lungimea fisierului

        int counter = 0;
        Character toReturn = null;
        for (String line : strings) {
            if(counter + line.length() > index){
                toReturn = line.charAt(index - counter);
            }
            else{
                counter += line.length();
            }
        }
        return toReturn;
    }

    public static void main(String[] args) {
        ArrayList<String> strings = new ArrayList<>();
        try {
            File myObj = new File("filename.txt");
            Scanner myReader = new Scanner(myObj);
            while (myReader.hasNextLine()) {
                String data = myReader.nextLine();
                strings.add(data);
            }
            myReader.close();

            System.out.println(getCharAtIndexFromString(strings, 12));
        } catch (FileNotFoundException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        }
    }
}