DataInputStream readInt() method in Java with Examples

05 Jun, 2020
The readInt() method of DataInputStream class in Java is used to read four input bytes and returns a integer value. This method reads the next four bytes from the input stream and interprets it into integer type and returns.
Syntax:
public final int readInt()
             throws IOException

Specified By: This method is specified by readInt() method of DataInput interface.
Parameters: This method does not accept any parameter.
Return value: This method returns the int value interpreted by the next four bytes of the input stream.
Exceptions:
EOFException – It throws EOFException if the input stream is ended before four bytes can be read.
IOException – This method throws IOException if the stream is closed or some other I/O error occurs.
Below programs illustrate readInt() method in DataInputStream class in IO package:
Program 1: Assume the existence of file “demo.txt”.
// Java program to illustrate// DataInputStream readInt() methodimport java.io.*;public class GFG {    public static void main(String[] args)        throws IOException    {          // Create integer array        int[] 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 (int b : buf) {            // Write integer value to            // the dataOutputStream            dataOutputStr.writeInt(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 integer values            System.out.println(                dataInputStr.readInt());        }    }}
Program 2: Assume the existence of file “demo.txt”.
// Java program to illustrate// DataInputStream readInt() methodimport java.io.*;public class GFG {    public static void main(String[] args)        throws IOException    {          // Create integer array        int[] buf = { 191, 225, 480, 763, 500 };          // Create file output stream        FileOutputStream outputStream            = new FileOutputStream("c:\\demo.txt");          // Create data output stream        DataOutputStream dataOutputStr            = new DataOutputStream(outputStream);          for (int b : buf) {            // Write integer value to            // the dataOutputStream            dataOutputStr.writeInt(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 integer values            System.out.println(                dataInputStr.readInt());        }    }}
References:https://docs.oracle.com/javase/10/docs/api/java/io/DataInputStream.html#readInt()
Java-Functions
Java-IO package
Java
Java
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