Writing to a specific line in a text file

Hi, I have a problem where I only want to replace one line in a text file, while keeping all the others the same. For example, my text file looks something like this:

0
3
10
18
7
4
2

And, in the actual program, I do something like this:
-Read line 3, set it to string x
-Change the value of string x

And now I want to replace line 3 with x, but I have no idea how to.

There are two ways:

1. Write to a temporary file sequentially, only writing out new data when you need to.
2. Use the RandomAccessFile class. See: Java Tips - How to use Random Access file and RandomAccessFile (Java 2 Platform SE v1.4.2)

Quote:

---

Originally Posted by The_Mexican

Hi, I have a problem where I only want to replace one line in a text file, while keeping all the others the same. For example, my text file looks something like this:

0
3
10
18
7
4
2

And, in the actual program, I do something like this:
-Read line 3, set it to string x
-Change the value of string x

And now I want to replace line 3 with x, but I have no idea how to.

---

here's an example

Code :

---

public class ReadWriteFile {
    public static void main(String[] args) throws FileNotFoundException, IOException{
        Formatter output = new Formatter(args[1]);
        Scanner sc = new Scanner ( new File(args[0]) );
        ....
        String replace = "x";
        while  (sc.hasNext() ){
            String line = sc.nextLine();
            .....
            if ( couter==3 ){
                line = replace;
            }
            output.format("%s\n", line );
        }
        output.close();
    }
}

---