The readDouble() method of DataInputStream class in Java is used to read eight input bytes and returns a double value. This method reads the next eight bytes from the input stream and interprets it into double type and returns.
Syntax:
public final double readDouble()
throws IOException
Specified By: This method is specified by readDouble() method of DataInput interface.
Parameters: This method does not accept any parameter.
Return value: This method returns the double value interpreted by the next eight bytes of the input stream.
Exceptions:
- EOFException – It throws EOFException if the input stream is ended before eight bytes can be read.
- IOException – This method throws IOException if the stream is closed or some other I/O error occurs.
Below programs illustrate readDouble() method in DataInputStream class in IO package:
Program 1: Assume the existence of file “demo.txt”.
// Java program to illustrate// DataInputStream readDouble() methodimport java.io.*;public class GFG { public static void main(String[] args) throws IOException { // Create double array double[] buf = { 10, 20, 30, 40, 50 }; // Create file output stream FileOutputStream outputStream = new FileOutputStream("c:\\demo.txt"); // Create data output stream DataOutputStream dataOutputStr = new DataOutputStream(outputStream); for (double b : buf) { // Write double value to // the dataOutputStream dataOutputStr.writeDouble(b); } dataOutputStr.flush(); // Create file input stream FileInputStream inputStream = new FileInputStream("c:\\demo.txt"); // Create data input stream DataInputStream dataInputStr = new DataInputStream(inputStream); while (dataInputStr.available() > 0) { // Print double values System.out.println( dataInputStr.readDouble()); } }} |
Program 2: Assume the existence of file “demo.txt”.
// Java program to illustrate// DataInputStream readDouble() methodimport java.io.*;public class GFG { public static void main(String[] args) throws IOException { // Create double array double[] buf = { 10.9, 20.8, 30.88, 40.76, 50.678 }; // Create file output stream FileOutputStream outputStream = new FileOutputStream("c:\\demo.txt"); // Create data output stream DataOutputStream dataOutputStr = new DataOutputStream(outputStream); for (double b : buf) { // Write double value to // the dataOutputStream dataOutputStr.writeDouble(b); } dataOutputStr.flush(); // Create file input stream FileInputStream inputStream = new FileInputStream("c:\\demo.txt"); // Create data input stream DataInputStream dataInputStr = new DataInputStream(inputStream); while (dataInputStr.available() > 0) { // Print double values System.out.println( dataInputStr.readDouble()); } }} |
References:
https://docs.oracle.com/javase/10/docs/api/java/io/DataInputStream.html#readDouble()
