readInt() | Java Practice

Answer:

DataInputStream

`readInt()`

Here is a program that reads four integers, adds them up, and writes the sum (as characters) to the monitor. It expects a data file intData.dat.

import java.io.*;
class ReadInts
{
 public static void main ( String[] args ) 
 {
   String fileName = "intData.dat" ;  
   long sum = 0;

   try
   {      
     DataInputStream instr = 
       new DataInputStream(
         new BufferedInputStream(
           new FileInputStream( fileName ) ) );

     sum += instr.readInt();
     sum += instr.readInt();
     sum += instr.readInt();
     sum += instr.readInt();
     
     System.out.println( "The sum is: " + sum );
     instr.close();
   }
   catch ( IOException iox )
   {
     System.out.println("Problem reading " + fileName );
   }
 }
}

The method readInt() grabs four bytes from the input stream and returns them as an int. That value can be used in arithmetic without conversion.

QUESTION 3:

Say that the file "intData.dat" was written by the following lines:

     out.writeInt(  0 );
     out.writeInt(  1 );
     out.writeInt(255 );
     out.writeInt( -1 );

What will the example program write on the monitor?