Writing a two dimensional array to a file in java

Question

I am trying to write a two dimensional array to a file using this simple code:

public void writeZ(PrintWriter out) { 
    for(int i=0;i<z.length;i++) {
    int count = 0;
    for (int j=0; j<z[i].length; j++) {
         out.print(z[i][j] + " ");
         count++;
    }
    System.out.print( count);
    out.println();
    }
}

Note: The count is just for debugging

My problem is that the file size doesn't match the array size.
The number of lines is correct (45) but the last line as 1643 numbers instead 6006 as in the array.

Any ideas what is the problem?

Community · Accepted Answer · 2017-05-23 12:27:16Z

5

You probably don't close the writer and don't call flush. Try doing this in the end:

out.flush();
out.close();

Also please see this for more information on the subject.

edited May 23, 2017 at 12:27

CommunityBot

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answered Sep 19, 2012 at 14:27

Ivan Koblik

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5 Comments

km1 Over a year ago

Close the writer from where it is opened. I personally don't like methods to close my Writers. Rule of thumb is if you didn't open it then you probably shouldn't close it.

Ivan Koblik Over a year ago

@km1 Absolutely agree, I haven't given a complete solution just an idea of what might be wrong. Also, it should be enough to just close the stream, as closing triggers flush.

jn1kk Over a year ago

@km1 How is that relevant? Ivan is not telling him to close it specifically in that method.

km1 Over a year ago

@jsn, just letting the OP know not to close it. He didn't specifically say in the method nor did he specify not in the method.

jn1kk Over a year ago

@km1 Then you are just assuming what he meant. For the love of God Ivan, please clarify to close it at the end of the program. XD

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