APCS/07 Trees/02 BXT/BXT_Driver.java

import java.util.*;

/*  Driver for the BXT class.
 *  Input: a postfix string with space delimited tokens. 
 */
public class BXT_Driver
{
   public static void main(String[] args)
   {
      ArrayList<String> postExp = new ArrayList<String>();
      postExp.add("2 3 + 5 / 4 5 - *");
   
      for( String postfix : postExp )
      {
         System.out.println("Postfix Exp: "  + postfix);
         BXT tree = new BXT();
         tree.buildTree( postfix );
         System.out.println("BXT: "); 
         System.out.println( tree.display() );
         System.out.print("Infix order:  ");
         System.out.println( tree.inorderTraverse() );
         System.out.print("Prefix order:  ");
         System.out.println( tree.preorderTraverse() );
         System.out.print("Evaluates to " + tree.evaluateTree());
         System.out.println( "\n------------------------");
      }
      
     /*  extension:  prints parentheses */
      BXT tree2 = new BXT();
      //tree2.buildTree("3 5 + 4 *");   // "( 3 + 5 ) * 4"         
      System.out.println(tree2.inorderTraverseWithParentheses()); 
   }
}

/***************************************

 Postfix Exp: 14 -5 /
 	-5
 /
 	14
 Infix order:  14 / -5 
 Prefix order:  / 14 -5 
 Evaluates to -2.8
 ------------------------
 Postfix Exp: 20.0 3.0 -4.0 + *
 		-4.0
 	+
 		3.0
 *
 	20.0
 Infix order:  20.0 * 3.0 + -4.0 
 Prefix order:  * 20.0 + 3.0 -4.0 
 Evaluates to -20.0
 ------------------------
 Postfix Exp: 2 3 + 5 / 4 5 - *
 		5
 	-
 		4
 *
 		5
 	/
 			3
 		+
 			2
 Infix order:  2 + 3 / 5 * 4 - 5 
 Prefix order:  * / + 2 3 5 - 4 5 
 Evaluates to -1.0
 ------------------------
 Postfix Exp: 5.6
 5.6
 Infix order:  5.6 
 Prefix order:  5.6 
 Evaluates to 5.6
 ------------------------
 
 *******************************************/