/**
    A class for testing the manipulation of algebraic expressions
*/

import java.util.*;

public class A5
{


  /**
      Tests a given algebraic expression by converting it
      to postfix and evaluating the expression.
      @param s the algebraic expression in infix form
      (tokens separated by spaces).
  */

  public static void testExpression(String s)                      {
    System.out.println(s);
    Expression expr = new Expression(s);
    String p = expr.convertToPostfix();
    System.out.println(p);
    try                                                          {
      System.out.println(expr.evaluate());                       }
    catch (IllegalArgumentException e)                           {
      System.out.print("illegal expression -- ");
      System.out.println(e.getMessage());                        }
    System.out.println();                                          }



  /**
      Perform the testing.
      @param args is ignored
  */

  public static void main(String[] args)                          {

    Queue q = new Queue();
    q.enqueue("hello");
    q.enqueue("there");
    q.enqueue("you");

    System.out.println(q.isEmpty());
    System.out.println(q.dequeue());
    System.out.println(q.dequeue());
    System.out.println(q.dequeue());
    System.out.println(q.isEmpty());

    System.out.println();
    System.out.println();

    testExpression("9");
    testExpression("3 + 4");
    testExpression("");
    testExpression("+");
    testExpression("3 4 5");
    testExpression("3 + 4 5");
    testExpression("3 +");
    testExpression("3 + * 5");
    testExpression("x + y - pi");
    testExpression("3 + 4 * 5");
    testExpression("3 * 4 + 5");
    testExpression("3 + 4 * ) + 6");
    testExpression("3 * 4 + 5 * 6");
    testExpression("3 + 4 * 5 * 6");
    testExpression("3 + 4 - 5 + 6");
    testExpression("2 * 3 * 10 + 6");
    testExpression("6 - 2 + 3 * 10");
    testExpression("1 + 2 * 3 * 10 + 4");
    testExpression("1 + 2 * 10 + 6 / 2");
    testExpression("1 + 2 * 10 + 1 + 6 / 2");
                                                                  }

}