File handling-streams

[Dayanand]

package streams;

import java.io.FileNotFoundException;
import java.io.PrintStream;

public class Mgr18Extend
{

public static void main(String[] args) throws FileNotFoundException
{

PrintStream p1 = new PrintStream("check.txt");
PrintStream p2 = System.out;

System.setOut(p1);

p1.println(1);
p2.println(2);
System.out.println(3);

System.setOut(p2);
p1.println(4);
p2.println(5);
System.out.println(6);

System.setOut(p1);
p1.println(7);
p2.println(8);
System.out.println(9);

}

}
output of check.txt:-
1
3
4
7
9

output of console:-
2
5
6
8

here p1 is pointing to file system(check.txt) where as p2 is pointing to console

but though i am printing 3 as System.out.println(3); it is not printing in the console,it is printing in the file(check.txt) y it so.?

[Tolls]

What do you think this line is doing:

System.setOut(p1);

?

[Dayanand]

What do you think this line is doing:

System.setOut(p1);

?

System.setOut(p2);
System.out.println(6);


but 6 is printing in the console,though System.setOut(p2); statement is there

[Tolls]

Yes.
And what is p2?

You didn't answer the question, though...what is setOut() doing?

[Dayanand]

Yes.
And what is p2?

You didn't answer the question, though...what is setOut() doing?

p2 is pointing to console which is a Stream variable.....

[Tolls]

So...when you System.setOut(p2) what is happening?

[Dayanand]

So...when you System.setOut(p2) what is happening?

i think p2 will be pointing to console...........?

[Tolls]

You shouldn't guess.
You should look at the API.

Reassigns the "standard" output stream.

It has no effect on p2. It is setting System.out.