Writing to files question

[Caleb Ash]

Okay, I have 4 files...

I really don't know how to do this,
I've been reading over my book "Blue Pelican Java",
on the section for appending but it doesn't make sense to me,
or at least I can't think of how to apply in the way I want.

I really only need 2 examples, one for the actNum situation,
and one for the other 3(as they use the same method).

I would be very thankful, and I know this isn't a code mill,but I cannot
figure this out


actNum.in | actPass.in | actIdnt.in | actAmt.in
0............ |.. 123245.. |.. Caleb A | 50.45

Each one has information on corresponding lines, as above

What code would i need to be able to produce the following things on a file(The ....'s are for spacing)

actNum would be automatic, 0 - what ever;
actPass on use input, same for actIdnt and actAmt;

actNum.in | actPass.in | actIdnt.in | actAmt.in
0............ | 123245 | Caleb A | 50.45
1............ | 846287 | Ryan Z | 134.21

[Adeiza Yusuf]

Hello, If I understand you correctly, you can make your method this simple and any time you call the method with the user information a space is given before the next is added.

public void addName(String userInput) throws IOException {

        FileWriter fw = null;
        try {
            fw = new FileWriter("     fileName.txt",true); //the true here indicates that it should be appended
            fw.write(userInput);

        }
        finally {
            if(fw!=null) {
                fw.close();
            }
        }

[Caleb Ash]

editting it a little bit:

public void addIn(String userInput, String file) throws IOException {

        FileWriter fw = null;
        try {
            fw = new FileWriter(file ,true); //the true here indicates that it should be appended
            fw.write(userInput);

        }
        finally {
            if(fw!=null) {
                fw.close();
            }
        }

So, I would use something like


addIn(pass.nextString(), actPass.in);


Correct?


Also, any idea about the actNum situation?
Where it would be the line number (Seeing as files counts the same as an array, first line is 0, 2nd line is 1)

[Adeiza Yusuf]

for the numbers you can use an int variable that you increment by 1 every time the file is written

[Campbell Ritchie]

You would do well to find out about BufferedWriters, which you will read about in the Java™ Tutorials. Remember to use a finally block to close your writer. You can write a whole line at once with a BufferedWriter.
Decide whether you wish to handle the IOException in your writing method.
It may be inefficient to call the method to write a single line, because you are repeatedly creating and deleting object references. See whether you can get the writing into a while loop. Again you will find similar examples in that Java™ Tutorials link I gave you.