Java read file into a char 2D array

Question

everyone. I have been thinking this for 3 hours, just cannot figure out. I have a program that requires reading the file into a 2D array. The file is like:

...##..#####........
########....####..##
.........##.........
#.#.#.#.#.#.#.#.#.#.

Basically, it is about a seat reservation system.

" . "means opened seats. " # " means reserved seats. The row and col are unknown to me, depend on the file. But every row has the same number of seats.

import java.util.Scanner;
import java.io.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.Arrays;


public class Main 
{   


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


    int rows = 0, cols = 0;
    char[][] auditorium = new char[rows][cols];

    Scanner sc = new Scanner(new BufferedReader(new FileReader("A1.txt")));

 }

I am new to java, really don't have any thoughts on this program. Please read the file and put the data into a char 2D array.

Combine the answers from stackoverflow.com/questions/2049380/reading-a-text-file-in-java and stackoverflow.com/questions/10751603/… to get what you want. — jrook
– jrook, Commented Feb 4, 2020 at 0:18
Also note that your auditorium array has been initialized with 0 rows and 0 columns. If you try to insert anything into this array, you could get an index out of exception. You could use a data structure that does not need to know the size of the input beforehand. An ArrayList might be useful to get around such problems. — jrook
– jrook, Commented Feb 4, 2020 at 1:23

Anuradha · Accepted Answer · 2020-02-04 04:03:31Z

0

Please check this code. It'll may help to you:

public static void main(String[] args) throws Exception {
    List<String> stringList = new ArrayList<>();
    Scanner sc = new Scanner(new BufferedReader(new FileReader("A1.txt")));
    while (sc.hasNext()) {
        stringList.add(sc.nextLine());
    }
    int rows = stringList.size();
    int cols = 0;
    if (rows > 0) {
        cols = stringList.get(0).length();
    }
    char[][] auditorium = new char[rows][cols];
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            auditorium[i][j] = stringList.get(i).charAt(j);
        }
    }
}

answered Feb 4, 2020 at 4:03

Anuradha

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1 Comment

Anuradha Over a year ago

I used answer suggested by @jrook to create this code.

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