Hi

I've written the following code for converting Postfix to Infix,it reads a string then reads it letter by letter ,a stack and a Tree is used,and I want to traverse the last object that has poped from the stack,in the following code I used this line:

System.out.println((Character)(((TreeNode)stack.pop()).data));

but it only prints the root of the tree,I tried to traverse it but I don't have any idea,I did sth like this( for traversing another node):

(TreeNode)stack.pop() = ( (TreeNode)stack.pop() ).data;
System.out.println((Character)(((TreeNode)stack.pop()).data));

but it didn't work.
would you plz help me with it.

Here is the code:

import java.util.Scanner;

public class Test
{
public static void main( String args[])
{

Scanner input = new Scanner( System.in );

System.out.printf("Enter your String(in Postfix):\n");
String c = input.nextLine();//read a line of text

Stack stack = new Stack();

int i = 0 ;
while( i < c.length() )
{

char a = c.charAt( i );

if( Character.isLetterOrDigit (a) )
{
System.out.printf("\n%c" , a );
stack.push( new TreeNode( a ) );
}

else if( a == '+' || a == '-' || a == '*' || a == '/' )
{
TreeNode t = new TreeNode( a );

t.insert( 0 , stack.pop() );

t.insert( 1 , stack.pop() );

stack.push( t );

}
i++;
}

(TreeNode)stack.pop() = ( (TreeNode)stack.pop() ).data; //<-----Here is the problem

System.out.println((Character)(((TreeNode)stack.pop()).data));

}

}



Thax
Bita