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() method import 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() method import 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()