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Object-Oriented Programming
Session 09
Student Name:
Roll/No:
Group:
I/O Streams
Java does provide support for I/O as it relates to files and networks. I/O in java is
performed through streams. A stream is nothing but an abstraction that either reads data
from a device or displays it on some output device. I/O classes and methods are applied
to any type of input, output device. We have to import java.io package while dealing
with I/O in java. Two types of streams are defined in Java: byte and character streams.
Let’s practice a few sample codes which can help us to improve our understanding of the
topic under discussion.
Experiment 1.0: Reading Console Input
import java.io.*;
class Read{
public static void main(String args[])
throws IOException
{
charc;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter characters and press q to quit”);
//reading characters
do
{
c=(char)br.read();
System.out.println(c);
}
while(c!=’q’);
}
}
Object-Oriented Programming
Experiment 1.1: Writing Console Output
import java.io.*;
class Write_Console
{
public static void main(String args[])
{
int b;
b=’A’;
System.out.write(b);
System.out.write(‘\n’);
}
}
Experiment 1.2: Reading and Writing file
import java.io.*;
import java.io.*;
class File_Display
{
public static void main(String args[])
throws IOException
{
int i;
FileInputStream fin;
try
{
fin=new FileInputStream(args[0]);
}
catch(“File Not Found”);
return;
}
catch(ArrayIndexOutOfBoundsException e)
{
System.out.println(“Display a file”);
return;
}
//read characters until End of File is found
Object-Oriented Programming
do
{
i=fin.read();
if(i!= -1)
System.out.println((char)i);
}
while(i!=-1)
Experiment 1.3: Task
Q1) By using the above techniques, copy a text file or java file to another already
created file. You have to mention the names of the source and destination files at runtime. Also count number of words in that file.
Q2) While compiling the above code, do mention such a name of destination file that
does not exist. And see what happens. If there is some error then correct it.
Q3) Write a code which reads string from the keyboard, and displays that on standard
output device. (This can set basis for a tiny editor design)
Q4) Write a code, which reads input from the console and displays it in a file.