//----------------------------------------------------------------------
// BalancedApp.java         by Dale/Joyce/Weems                Chapter 3
//
// Checks for balanced grouping symbols.
// Input consists of a sequence of expressions, one per line.
// Special symbol types are (), [], and {}.
//----------------------------------------------------------------------

import java.util.Scanner;

public class BalancedApp 
{
  public static void main( String[] args )
  {
    Scanner conIn = new Scanner( System.in );

    // Instantiate new Balanced class with grouping symbols.
    Balanced bal = new Balanced( "([{", ")]}" );
    
    int result;                  // 0 = balanced, 1 = unbalanced,
                                 // 2 = premature end

    String expression = null;    // expression to be evaluated
    String more = null;          // used to stop or continue processing

    do
    {
      // Get next expression to be processed.
      System.out.println( "Enter an expression to be evaluated: " );
      expression = conIn.nextLine();
      
      // Obtain and output result of balanced testing.
      result = bal.test( expression );
      if ( result == 1 )
        System.out.println( "Unbalanced symbols" );
      else
      if ( result == 2 )
        System.out.println( "Premature end of expression" );
      else
        System.out.println( "The symbols are balanced." );

      // Determine if there is another expression to process.
      System.out.println();
      System.out.print( "Evaluate another expression? (Y=Yes): " );
      more = conIn.nextLine();
      System.out.println();
    }
    while ( more.equalsIgnoreCase( "y" ) );
  }
}