Need Help understanding method

Question

public static double[][] readFile(java.io.File file)

throws java.io.FileNotFoundException

Reads from a file and returns a ragged array of doubles The maximum rows is 10 and the maximum columns for each row is 10

Each row in the file is separated by a new line Each element in the row is separated by a space Suggestion: You need to know how

many rows and how many columns there are for each row to create a ragged array. 1. Read the doubles from the file into an a

temporary array [10][10] of Strings which was initialized to nulls. 2. Find out how many rows there are (any row that has the first

element != null is a valid row) 3. Create the array based on the num of rows, i.e. double[][]array = new double[#rows][] 4.

Determine the number of columns for the first row (any element != null is a valid element) 5. Create the first row, i.e. array[0] =

new double[#columns] 6. Put the values from the temporary array into in the row (don't forget to convert from strings to doubles)

7. Repeat for all rows

Parameters:

file - the file to read from

Returns:

a two dimensional ragged (depending on data) array of doubles if the file is not empty, returns a null if file is empty

Throws:

java.io.FileNotFoundExceptio

I am stuck on understanding what this method wants

my code right now

public class TwoDimRaggedArrayUtility {

public static double[][] readFile (File file) throws FileNotFoundException{

Scanner sc = new Scanner(file);

}

}

Answer 1

import java.io.*;

class AngieARaggedInput

{

public static final int MAX=10;

double [][] readFile( File file)

{

String inbuff;

double [][] A = new double[MAX][MAX];

//initializes the array

for (int i=0; i<MAX; i++)

{

for (int j=0; j<MAX; j++)

{

A[i][j]=0;

}

}

try

{

String fileName = file.getName();

BufferedReader bufferedReader = new BufferedReader( new FileReader(fileName));

for (int iLoop=0; iLoop<MAX; iLoop++)

{

inbuff = bufferedReader.readLine();

if (inbuff==null) { break; }

String tokens[] = inbuff.split(" ");

int iIndexPos = 0;

for (int jLoop=0; jLoop<tokens.length; jLoop++) // for each token that is parsed....

{

if (iIndexPos<MAX) // the array is not full

{

if (tokens[jLoop].length()>0) // the token has data

{

A[iLoop][iIndexPos++] = Double.parseDouble(tokens[jLoop]); //converts to double and stores it

}

}

else // the array is full...bails out

{

break;

}

}

} //for iLoop

} //try

catch (IOException ex)

{

}

return(A);

} //readFile

public static void main(String args[])

{

File infile = new File ("dblAmounts.dat");

AngieARaggedInput x = new AngieARaggedInput();

double A[][] = x.readFile(infile);

for (int iLoop=0; iLoop<A.length; iLoop++)

{

for (int jLoop=0; jLoop<A[iLoop].length; jLoop++)

{

if (A[iLoop][jLoop]!=0)

{

System.out.print(A[iLoop][jLoop] + " ");

}

}

System.out.println(" ");

}

}

}