Matrix Program - First time using multiple classes

Question

I'm writing a program right now that takes matrices from an input file specified by the user. The file is in this format.
#rows #columns
1 1 1 1 1 1
1 1 1 1 1 1
1 1 1 1 1 1
So in place of #rows I would have a 3, and #columns would be a 6. They are seperated by a space, as are the elements.
I have two classes, one entitled Proj6 (Yes, it's a school assignment) and one called Matrix. Proj6 chooses the name of the file to use. After the Matrix class creates the two matrices, using loops, Proj6 then asks what I would like to do to these matrices. I must be able to:
Print the two Matrices
Add
Subtract (just in the order of Matrix 1 - Matrix 2)
Transpose Matrix one.
Quit the program.
Here is my Proj6 Class:
public class Proj6 {
     public static Scanner s;
     public static Scanner f;
     public static void main(String[]args) throws FileNotFoundException {
          System.out.print("Please Enter the filename, complete with extension: ");
          s = new Scanner(System.in);
          f = new Scanner(new File(s.nextLine()));
          String fline = (f.nextLine());
          StringTokenizer st = new StringTokenizer(fline ," ");
          String r = st.nextToken();
          int row = Integer.parseInt(r);
          String c = st.nextToken();
          int col = Integer.parseInt(c);
          Matrix m1 = new Matrix(row,col);
          for (int i = 0; i < row; i++){
               fline = (f.nextLine());
               for (int j = 0; j < col; j++){
                    while (st.hasMoreTokens()){
                    String x = st.nextToken();
                    int value = Integer.parseInt(x);                              
                    m1.setElem(i,j,value);     
          f.nextLine();
          fline = (f.nextLine());
          r = st.nextToken();
          row = Integer.parseInt(r);
          c = st.nextToken();
          col = Integer.parseInt(c);
          Matrix m2 = new Matrix(row,col);
          for (int o = 0; o < row; o++){
               fline = (f.nextLine());
               for (int j = 0; j < col; j++){
                    while (st.hasMoreTokens()){
                    String x = st.nextToken();
                    int value = Integer.parseInt(x);                              
                    m2.setElem(o,j,value);                    
          System.out.println("Enter (p)rint, (a)dd, (t)ranspose, or (q)uit");
          String a = s.nextLine();
          char action = a.charAt(0);
          if (action == 'p') {
                    String print1 = Matrix.toString(m1);
                    System.out.println("First");
                    System.out.println();
                    System.out.print(print1);
                    String print2 = Matrix.toString(m2);
                    System.out.println("Second");
                    System.out.println();
                    System.out.print(print2);
          else if (action == 'a') {
          else if (action == 't') {
                    Matrix m1t = new Matrix(transpose(m1));
                    Matrix m2t = new Matrix(transpose(m2));
                    String print1 = Matrix.toString(m1t);
          else {
                    System.exit(-1);
}Here is my "Matrix" class
import java.util.*;
public class Matrix {
     public int row;
     public int col;
     public int[][] arr = new int[row][col];
     Matrix (int row, int col) {
          arr = new int[row][col];          
     public void setElem(int row, int col, int value) {
          arr[row][col] = value;
     public String toString (Matrix m){
          return null;
     public Matrix plusMatrix (Matrix m) {
          if (m1.length != m2.length || m1.length[0] != m2.length[0]) {
               return null;
          Matrix x = new Matrix(m1.length,m1.length[0]);
          int number;
          for (int i = 0; i<m1.length; i ++) {
               for (int j = 0; j<m1[0].length; j ++) {
                    number = (Integer.parseInt(m1[i][j]) + Integer.parseInt(m2[i][j]));
                    x.setElem(i,j,number);
          return x;
     public Matrix minusMatrix(Matrix m) {
          Matrix x = new Matrix(m1.length, m1.length[0]);
          return x;
     public Matrix transpose (Matrix m) {
          int number;
          Matrix x = new Matrix(m1.length[0],m1.length);
          for (int i = 0; i< m1.length[0]; i ++) {
               for (int j = 0; j<m1.length; j ++) {
                    number = Integer.parseInt(m1[i][j]);
                    x.setElem(i,j,number);                    
          return x;
}I'm having two main problems:
First, my references to "m1" and "m2" in the Matrix class get the cannot be resolved errors. Once I've created the matrices correctly (in theory) why can't I refer to them in Matrix?
Second, I don't think that I'm creating the matrix quite correctly. I know that Tokenizer is technically obsolete, but I'm more familiar with it than the split method.
I'm required to use a toString method in Matrix to "Print" the matrices from each function, but I'm not allowed to send it any parameters, or use any print statements in the Matrix class.
Can you guys catch any errors that I can rectify without necessarily changing my techniques? Or at least provide a thorough explanation for any technique changes?

Answer 1

My new, updated code is having trouble getting the Matrices inputted correctly
public class Proj6 {
     public static Scanner s;
     public static Scanner f;
     public static void main(String[]args) throws FileNotFoundException {
          System.out.print("Please Enter the filename, complete with extension: ");
          s = new Scanner(System.in);
          f = new Scanner(new File(s.nextLine()));
          String fline = (f.nextLine());
          StringTokenizer st = new StringTokenizer(fline ," ");
          int row = Integer.parseInt(st.nextToken());
          int col = Integer.parseInt(st.nextToken());
          Matrix m1 = new Matrix(row,col);
          System.out.println(row + "  " + col);
          System.out.print(fline);
          f.nextLine();
          f.nextLine();
          fline = f.nextLine();
          for (int i = 0; i < row; i++){               
               while (st.hasMoreTokens()) {
                    int value = Integer.parseInt(st.nextToken());
                    System.out.println(value);
                    for (int j = 0; j < col; j++){
                         m1.setElem(i,j,value);     
               fline = (f.nextLine());
          //System.out.println(toString());
          System.out.println(fline);
          System.out.println("Here begins the second matrix");
          int row2 = Integer.parseInt(st.nextToken());
          int col2 = Integer.parseInt(st.nextToken());
          System.out.print(row2 + "  " + col2);
          Matrix m2 = new Matrix(row2,col2);
          for (int o = 0; o < row2; o++){
               f.nextLine();
               while (st.hasMoreTokens()) {
                    int value = Integer.parseInt(st.nextToken());
                    for (int j = 0; j < col2; j++){
                         m2.setElem(o,j,value);                    
          }When I run this code with this matrix file:
3 5
8 19 7 15 4
21 42 9 0 26
13 7 2 1 16
4 5
2 12 6 9 0
40 22 8 4 17
3 13 8 29 10
1 1 1 1 1 I get:
3 5
3 52 12 6 9 0
Here begins the second matrix
it's not moving through correctly. The f.nextLine()operator, and its relation to the string fline is confusing me.
Edited by: Ryanman on Apr 7, 2010 9:31 PM