output recursive to text file

[John Philippe]

Good evening,

I am fairly new at java and need help.

I have spent so much time trying to understand how to output my recursive solution to the tower of hanoi problem that I am now having a hard time seeing where I am going wrong.
I would like to output my result into a text file, instead of having this expected resulted in my text file as follows:

1 --> 3
1 --> 2
3 --> 2
1 --> 3
2 --> 1
2 --> 3
1 --> 3

I get this in my text file:
1 --> 3

To me it looks like my code solution is not going through the whole recurtion but I don't know how to fix it.
If somebody could help me, I would really really appreciate it.

  import java.io.FileOutputStream;
import java.io.PrintStream;

public class TowersOfHanoi
{
	private int numDisks;//Variable representing the number of disks to move
	
	public TowersOfHanoi( int Disks )
	{
		int disks = 0;
		setNumDisks(disks);
	} //end TowersOfHanoi constructor
	
	// Recursively move the disks through the towers
	public void solveTowers( int disks, int sourcePeg, int destinationPeg, int tempPeg)
	{
		try
		{
			
    		PrintStream stdOut = new PrintStream(new FileOutputStream ("TowerOfHanoi.txt"));
                                System.setOut(stdOut);
            
    		//Base case -- only one disk to move
    		if ( disks == 1 )
    		{
                
    			System.out.printf( "\n%d --> %d", sourcePeg, destinationPeg );
    			return;
    		} //end if
            
    		//recursion step -- move disk to tempPeg, then to destinationPeg
    		//move(disk -1) disks from sourcePeg to tempPeg recursively
    		solveTowers( disks - 1, sourcePeg, tempPeg, destinationPeg );
		            
    		//move the last disk from the sourcePeg to the destinatinPeg
    		System.out.printf( "\n%d --> %d", sourcePeg, destinationPeg );

    		// Move(disk-1) disks from tempPeg to destinationPeg
    		solveTowers( disks - 1, tempPeg, destinationPeg, sourcePeg );
    	       		
                }
                catch (Exception e)
                {
                System.out.println(e.getMessage());}
                }
			
	public void setNumDisks(int numDisks) 
	{
		this.numDisks = numDisks;
	}

	public int getNumDisks()
	{
		return numDisks;
	
	}
}//end class TowersOfHanoi

  

Thank you in advance,
John

[Henry Wong]

Basically, you are recursively opening the same file -- which of course, overwrites each other.

Henry

[John Philippe]

Thank you for such a quick response Henri.

May I ask you, how I could avoid writing over it?
And obtain my desired output

Thank you

John

[David Newton]

Why do you ignore the constructor parameter? How are you starting the run, considering the first question? Why do you overwrite the file each move?

[David Newton]

Don't keep opening it.

[John Philippe]

good morning,

I run it with this:

  
public class TowersOfHanoiExecute 
{
	
	public static void main(String[] args) 
	{// TODO Auto-generated method stub
		int startPeg = 1; //Value 1 is used to indicate startPeg in output
		int endPeg = 3; //Value 3 is used to indicate endPeg in output
		int tempPeg = 2; //Value 2 is used to indicate tempPeg in output
		int totalDisks = 3; //number of disks
		TowersOfHanoi towersOfHanoi = new TowersOfHanoi( totalDisks );
		
		//initial nonrecursive call: move all disks.
		towersOfHanoi.solveTowers( totalDisks, startPeg, endPeg, tempPeg );
	}//end main

}//end class TowersofHanoiExecute
  

Could somebody please help me with how NOT to keep on re-opening it?

Thank you,

John

[fred rosenberger]

well, each time you enter your "solveTowers" method, there is a call to open the file. So, move your opening of the file to outside the method.

[John Philippe]

thank you Fred,
I will try that

John

[Sridhar Gudipalli]

[solution removed]

[John Philippe]

Thank you Sridhar Gudipalli,

I now have to study your example so I can comprehend what was done.

John

[David Newton]

@Sridhar: http://faq.javaranch.com/java/DontBeACodeMill

IMO the point is to help people learn how to learn, not give them answers on a plate.

[fred rosenberger]

David Newton wrote:IMO the point is to help people learn how to learn, not give them answers on a plate.

That's our philosophy, too. I removed the solution, although it may be too late.

[John Philippe]

Good evening,

I apologize in my slownest to respond but quite a lot happens in a day, and I like to study and try out what I am given before responding, and I'm really slow at that.

The code that Sridhar Gudipalli provided me with was extremely helpful, and I would like to thank him once again for I spent so much time on this trying to get it to work on my own and really truely couldn't; that's why when I get stuck like that I come and humbly ask the help of the people that knows.

I looked and spent a good amount of time through the code to make sure I understood it, once again thank you for your all's help.

John.