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Java RandomAccessFile writeDouble() Method with Example

RandomAccessFile Class writeDouble() method: Here, we are going to learn about the writeDouble() method of RandomAccessFile Class with its syntax and example.
Submitted by Preeti Jain, on March 23, 2020

RandomAccessFile Class writeDouble() method

• writeDouble() method is available in java.io package.
• writeDouble() method is used to first change the double value to long value by using doubleToLongBits() and then long value writes to the file up to 8 bytes.
• writeDouble() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• writeDouble() method may throw an exception at the time of writing double value.
  IOException: This exception may throw an exception while performing input/output operation.

Syntax:

    public final void writeDouble(double val);

Parameter(s):

• double val – represents the double value to write.

Return value:

The return type of this method is void, it returns nothing.

Example:

// Java program to demonstrate the example 
// of void writeDouble(double val) method of
// RandomAccessFile

import java.io.*;
class RAFWriteDouble {
 public static void main(String[] args) throws Exception {
  double db = 12548.2658;
  // Instantiate a random access file
  // object with file name and permissions
  RandomAccessFile ra_f = new RandomAccessFile("e:/includehelp.txt", "rw");

  // By using writeDouble() method is to 
  // write double value to the file

  ra_f.writeDouble(db);

  // by using seek() method is to 
  // set the current file indicator
  // from where read/write could 
  // start i.e. we set here 0 so reading
  // will be done from 0 till EOF
  ra_f.seek(0);

  // By using readDouble() method is to 
  // read a double from this file

  System.out.print(" ra_f.readDouble(): " + ra_f.readDouble());

  // By using close() method isto
  // close this stream ran_f
  ra_f.close();
 }
}

Output

  ra_f.readDouble(): 12548.2658