Question

I have a problem with matrix. I have a matrix in txt file. This matrix looks:

231 324 123
345 565 234
657 234 654

I want to replacement elements to form:

654 234 657
234 565 345
231 324 123

I have a algorithm with replacement elements: 3-1-i, where i is number of choosen element from array. I have a problem how I read file and save elements to array and how implement this loop. This is my try with reading txt file and saving elements to array:

    List<String[]> rows = new ArrayList<String[]>();
    while ((line = bfr.readLine()) != null) {
        String[] row = line.split(" ");
         rows.add(row);

       }
    System.out.println(rows.toString());  

But I get [Ljava.lang.String;@525483cd as result.
Can anyone help me with this loop and reading this matrix?

Answer 1

Note : I used String s with newline characters \n, works the same way if the string is gotten from a file.

import java.io.*;
import java.util.StringTokenizer;

public class file {
public static void main(String args[]) throws IOException {

String s = "231 324 123 \n 345 565 234 \n 657 234 654";

StringTokenizer n = new StringTokenizer(s);
String [] arr = new String[9];
int nn = 0;
 while(n.hasMoreElements()){
    arr[nn] =  n.nextToken();
    nn+=1;
}

for(int iii = (arr.length -1); iii >=0 ; iii--){
   System.out.print(arr[iii] + "  ");

    if((iii % 3) == 0) {
        System.out.println();
    }
}

}



}

Output is

654 234 657
234 565 345
123 324 231

Edit To read the string from file

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

int i;
FileInputStream fin = new FileInputStream("files.txt");
String n = "";

do {
     i = fin.read();
     n += (char) i;
   } while(i != -1);

   fin.close();
//String n now contains the contents of the file
}