//  Convert.java  Copyright (c) 2005 Kari Laitinen

//  http://www.naturalprogramming.com

//  2004-10-03  File created.
//  2005-05-26  String method contains() used instead of indexOf()
//  2008-02-03  Last modification.

//  The best way to execute this program is to run it in a
//  command prompt window where command line parameters can
//  be given. It may be difficult, and even impossible, to
//  supply the command line parameters if this program is 
//  executed with a modern development tool such as JCreator
//  or Eclipse.

//  This program will, though, ask for data from the user
//  if no command line parameters are given.

//  More notes at the end of this file:

import java.util.* ;

class  Conversion
{
   String  first_unit ;
   String  second_unit ;
   double  conversion_constant ;

   public Conversion( String  given_first_unit,
                      String  given_second_unit,
                      double  given_conversion_constant )
   {
      first_unit   =  given_first_unit ;
      second_unit  =  given_second_unit ;
      conversion_constant  =  given_conversion_constant ;
   }

   public void convert( String  given_unit,
                        double  amount_to_convert )
   {
      if ( first_unit.contains( given_unit ) )
      {
         System.out.print(  "\n  "  +  amount_to_convert  +  " "
                         +  first_unit  + " is "
                         +  amount_to_convert * conversion_constant
                         +  " "  +  second_unit ) ;
      }

      if ( second_unit.contains( given_unit ) )
      {
         System.out.print( "\n  "  +  amount_to_convert  +  " "
                         +  second_unit  + " is "
                         +  amount_to_convert / conversion_constant
                         +  " "  +  first_unit ) ;
      }
   }
}

class  Convert
{
   public static void main( String[]  command_line_parameters )
   {
      Scanner  keyboard  =  new Scanner( System.in ) ;

      Conversion[]  conversion_table  =  new  Conversion[ 13 ] ;

      conversion_table[ 0 ] = new Conversion("meters", "yards", 1.093613 );
      conversion_table[ 1 ] = new Conversion("meters", "feet",  3.280840 );
      conversion_table[ 2 ] = new Conversion("miles",  "kilometers",1.609344);
      conversion_table[ 3 ] = new Conversion("inches", "centimeters", 2.54 );
      conversion_table[ 4 ] = new Conversion("acres",  "hectares", 0.4046873);
      conversion_table[ 5 ] = new Conversion("pounds", "kilograms",0.4535924);
      conversion_table[ 6 ] = new Conversion("ounces", "grams",    28.35 );
      conversion_table[ 7 ] = new Conversion("gallons (U.S.)","liters", 3.785);
      conversion_table[ 8 ] = new Conversion("gallons (Br.)", "liters", 4.546);
      conversion_table[ 9 ] = new Conversion("pints (U.S.)",  "liters", 0.473);
      conversion_table[ 10 ]= new Conversion("pints (Br.)",   "liters", 0.568);
      conversion_table[ 11 ]= new Conversion("joules",       "calories",4.187);
      conversion_table[ 12 ]= new Conversion("lightyears",   "kilometers",
                                                              9.461e12 ) ;
      String  unit_from_user ;
      int     amount_to_convert ;

      if ( command_line_parameters.length  ==  2 )
      {
         unit_from_user     =  command_line_parameters[ 0 ]  ;
         amount_to_convert  =  Integer.parseInt(
                                        command_line_parameters[ 1 ] ) ;
      }
      else
      {
         System.out.print( "\n Give the unit to convert from: " ) ;
         unit_from_user  =  keyboard.nextLine() ;
         System.out.print( " Give the amount to convert:   " ) ;
         amount_to_convert  =  Integer.parseInt( keyboard.nextLine() ) ;
      }

      for ( int conversion_index  =  0 ;
                conversion_index  <  conversion_table.length ;
                conversion_index  ++ )
      {
         conversion_table[ conversion_index ].convert( unit_from_user,
                                                       amount_to_convert ) ;
      }
   }
}




/*

//  NOTE:

//  The Scanner method nextInt() does not work properly
//  after the use of method nextLine(). For this reason it is
//  best to input everything with the nextLine() method in programs
//  where nextLine() must be used.

//  The statement
//     amount_to_convert  =  Integer.parseInt( keyboard.nextLine() ) ;
//  means the same as
//     amount_to_convert  =  keyboard.nextInt() ;


//  NOTE:

//  Another possibility to build the conversion table in this program
//  is to create an initialized array of objects in the following way:

      Conversion[]  conversion_table  =

         {  new Conversion("meters", "yards", 1.093613 ),
            new Conversion("meters", "feet",  3.280840 ),
            new Conversion("miles",  "kilometers",1.609344),
            new Conversion("inches", "centimeters", 2.54 ),
            new Conversion("acres",  "hectares", 0.4046873),
            new Conversion("pounds", "kilograms",0.4535924),
            new Conversion("ounces", "grams",    28.35 ),
            new Conversion("gallons (U.S.)","liters", 3.785),
            new Conversion("gallons (Br.)", "liters", 4.546),
            new Conversion("pints (U.S.)",  "liters", 0.473),
            new Conversion("pints (Br.)",   "liters", 0.568),
            new Conversion("joules",       "calories",4.187),
            new Conversion("lightyears",   "kilometers", 9.461e12 )
         } ;



*/