Write double to a file

Question

I want to write doubles to a file without converting them to string....... how is this done?

Answer 1

The text file showed me squares so I could not see the hexadecimal numbers.. Then I used the bin file and I could see hexadecimal numbers.
Since I want to sort the numbers... I am wondering how I would specifically get that double number again using the input stream..
I did this:
          /*Create file or overwrite if it does exists*/
          FileInputStream fis = new FileInputStream("File1.bin");
          DataInputStream dis = new DataInputStream(fis);
          int size = fis.available();
          System.out.println("Size of File1 "+size);
          /*Get random number*/
          /*Create an array that can store 100,000 numbers*/
          double num1[] = new double[100001];
          //Write to file
          for (int count = 0; count <= size; count ++)
               num1[count] = dis.readDouble(num1[count]); ------This line problem
               System.out.println(num1[count]);
In the API - double readDouble() is method under DataInputStream but when I compile this...
This is the error I get:
SingleThread.java:28: readDouble() in java.io.DataInputStream cannot be applied
to (double)
num1[count] = dis.readDouble(num1[count]);