Using BufferedReader in java to read a line of ints before reading lines of Strings from a text file

Question

I have a text file that looks like this:

5 10
ahijkrewed
llpuvesoru
irtxmnpcsd
kuivoqrsab
eneertlqzr
tree
alike
cow
dud
able
dew

The first number on the first line, 5, is the number of rows for a word-search puzzle, and 10 is the number of columns for the puzzle. The next five lines is the puzzle. I need to know how to place 5 into a rows integer, and 10 to a columns integer. Then I need to skip to the next line to read the strings. Using a modified file with only the 5 lines for the puzzle I figured out how to place the puzzle portion into a 2d array, but I need a way to set the size of that array from the first line of the proper text fle.

I wrote this:

import java.io.*;

class SearchDriver {
public static void processFile(String filename) throws FileNotFoundException, IOException {

    FileReader fileReader = new FileReader(filename);
    BufferedReader in = new BufferedReader(fileReader);

    // declare size of array needed
    //
    // int rows and columns need to be read in from first
    // line of the file which will look like: X Y
    //
    // so i need rows = X and columns = Y
    int rows = 5;
    int columns = 10;
    String[][] s = new String[rows][columns];

    // start to loop through the file
    //
    // this will need to start at the second line of the file
    for(int i = 0; i < rows; i++) {
        s[i] = in.readLine().split("(?!^)");
    }

    // print out the 2d array to make sure i know what i'm doing
    for(int i=0;i<rows;i++) {
        for(int j=0;j<columns;j++) {
            System.out.println("(i,j) " + "(" + i + "," + j + ")");
            System.out.println(s[i][j]);
        }
    }
}
public static void main(String[] args)
    throws FileNotFoundException, IOException {
        processFile("puzzle.txt");
        }
    }

Any help would be appreciated including any websites with examples and extensive documentation on reading in files using BufferedReader.

Answer 1

I'd suggest a simpler solution: Use java.util.Scanner instead. There are lots of examples of use online (and in the link I provided), but this might get you started:

Scanner sc = new Scanner(new File(filename));
int rows = sc.nextInt();
int cols = sc.nextInt();
sc.nextLine();  // move past the newline
for(int i = 0; i < rows; i++) {
  String line = sc.nextLine();
  // etc...
}

Answer 2

This seems like homework, so I won't give you the whole solution, but here's a hint to get you started:

String firstLine = in.readLine();
//You now have the two integers in firstLine, and you know that they're 
//separated by a space. How can you extract them into int rows and int columns?
String[][] s = new String[rows][columns];