How do you scan individual characters from each line of string in a .txt file into a 2D array?

Question

First of all, thank you for coming and taking the time to help with the problem.

I have spent countless hours searching all over and still have not found a working solution to my problem: How do you use the scanner to scan individual characters from each line of string in a .txt file into a 2D array of unknown dimensions?

Problem 1: How do you determine the number of columns of an unknown .txt file? Or is there a better method of determining the size of an unknown 2d array with the .nextInt() method and how?

Problem 2: How do you print out a 2d array without weird [@#$^@^^ errors on the console?

Problem 3: How do you get the scanner to print any character that it reads from the .txt file onto the console (with 2d arrays (yes I know, arrays of arrays))?

Here's my incomplete code to give you an idea of the problem:

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

public class LifeGrid {

public static void main(String[] args) throws Exception {

    Scanner scanner = new Scanner(new File("seed.txt"));

    int numberOfRows = 0, columns = 0;


    while (scanner.hasNextLine()) {
        scanner.nextLine();
        numberOfRows++;

    }

    char[][] cells = new char[numberOfRows][columns];

    String line = scanner.nextLine(); // Error here
    for (int i = 0; i < numberOfRows; i++) {
        for(int j = 0; j < columns; j++) {
            if (line.charAt(i) == '*') {
            cells[i][j] = 1;
            System.out.println(cells[i][j]);
            }
        }
    }
    System.out.println(numberOfRows);
    System.out.println(columns);
  }
}

Answer 1

A scanner once used can't be reset to the starting position. You have to create a new instance again. I've modified your code to possibly achieve what you're trying to do -

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

public class LifeGrid {

public static void main(String[] args) throws Exception {

    Scanner scanner = new Scanner(new File("seed.txt"));

    int numberOfRows = 0, columns = 0;

    while (scanner.hasNextLine()) {
        String s = scanner.nextLine();
        if( s.length() > columns ) columns = s.length();
        numberOfRows++;

    }

    System.out.println(numberOfRows);
    System.out.println(columns);
    char[][] cells = new char[numberOfRows][columns+1];

    scanner = new Scanner(new File("seed.txt"));
    for (int i = 0; i < numberOfRows; i++) {
        String line = scanner.nextLine();
        System.out.println("Line="+line+", length="+line.length());
        for(int j = 0; j <= line.length(); j++) {
            if( j == line.length() ) {
                cells[i][j] = (char)-1;
                break;
            }
            cells[i][j] = line.charAt(j);
        }
    }
    System.out.println(numberOfRows);
    System.out.println(columns);
    for (int i = 0; i < numberOfRows; i++) {
        for(int j = 0; j <= columns; j++) {
                if( cells[i][j] == (char)-1 ) break;
                System.out.println("cells["+i+"]["+j+"] = "+cells[i][j]);
        }
    }
  }
}