import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import java.lang.*;

/**
 * This class (applet) models a ft-inch-sixteenth calculator
 */
 public class calculator extends Applet implements ActionListener, ItemListener {
  /**
   * called when the foot button is depressed
   *
   *   footButton can only be called once when entering a number - this method
   *   checks this automatically
   */

  public calculator ( ) {
  }

  /**
   * when the foot button is depressed
   */
  private void footButton ( ) {
    // verify that the foot button has not been pressed
    if ( this.ft_pressed == false ) {
      // tell the program that the foot button has been pressed
      this.ft_pressed = true;
      // update the display to indicate this
      this.display.setText ( this.addFoot( this.display.getText() ) );
      this.enableFeet();
    }
  }

  /**
   * perform an addition operation
   */
  private void addButton ( ) {
    this.resetFlags();
    // perform the operation
    this.performOperation( this.cvtDisplay ( this.display.getText() ) , this.ADD );
    // output the result
    this.display.setText( this.getResult() );
  }

  /**
   * perform a end result
   */
  private void eqButton ( ) {
    this.resetFlags();
    // output the result
    this.performOperation( this.cvtDisplay ( this.display.getText() ) , this.INITIAL );
    this.display.setText( this.getResult() );
  }

  /**
   * perform a subtraction operation
   */
  private void subButton ( ) {
    this.resetFlags();
    // perform the operation
    this.performOperation( this.cvtDisplay( this.display.getText() ) , this.SUB );
    // output the result
    this.display.setText( this.getResult() );
  }

  /**
   * perform a multiplication operation
   */
  private void mulButton ( ) {
    this.resetFlags();
    // perform the operation
    this.performOperation( this.cvtDisplay ( this.display.getText() ) , this.MUL );
    // output the result
    this.display.setText( this.getResult() );
  }

  /**
   * perform a division operation
   */
  private void divButton ( ) {
    this.resetFlags();
    // perform the operation
    this.performOperation( this.cvtDisplay ( this.display.getText() ) , this.DIV );
    // output the result
    this.display.setText( this.getResult() );
  }

  /**
   * clear button returns the calculator to the initial state
   */
  private void clearButton ( ) {
    // set all of the flags to false
    this.resetFlags();
    // reset the display
    this.opBuffer1 = 0;
    this.display.setText( this.getResult() );
    this.operation1 = this.ADD;
  }

  /**
   * decimal button
   */
  private void decButton ( ) {
    if ( ! this.decPressed ) {
      this.decPressed = true;
      if ( this.operation || this.initState )
        this.display.setText( "0." );
      else
        this.display.setText( display.getText() + "." );
   }
      if ( this.initState )
      this.initState = false;
  }

 /**
  * called whenever a numeric button is pressed
  *
  *   logic in numeric button:
  *     user enters a sequence of integers representing feet until he selects
  *     an operation ( see operation logic ), or the foot symbol. When he selects
  *     the foot symbol, a switch indicates this
  */
 private void numericButton ( int i ) {

   // if someone previously hit an operation button
   if ( this.operation ) {
     // acknowledge and reset operation
     this.operation = false;
     // clear the display
     if ( ! this.decPressed )
       this.display.setText( "" );
     else
       this.display.setText( this.display.getText() );
   }

   // a string to hold the current display
   String display = this.display.getText();

   // if the calc has been cleared or is in initial state - ready for input
   // can only accept 0-9 until foot has been pressed
   if ( this.initState && this.ft_pressed == false && i <= 9 && i >= 0 &&
        ! this.decPressed ) {
     this.display.setText( "" + i );
   }

   // if the user is continuing to enter feet - feet must not be pressed and
   // digits can only be 1- 9
   else if ( this.ft_pressed == false && i <=9 && i >= 0 ) {
     this.display.setText( display + i );
   }

   // if the calculators ft has been pressed, then we are gathering either 1 or
   // 2 more keystrokes - the first can be 0 - 11
   else if ( this.ft_pressed == true && this.inch_pressed == false &&
             this.sixTeenth_pressed == false && i >= 0 && i <= 11 ){
     // if this.inch == false, then this is the keystroke which is selecting
     // an inch
     if ( this.inch_pressed == false )
       this.inch_pressed = true;
     this.display.setText ( this.addInch( this.display.getText(), "" + i ) );
   }


   else if ( this.ft_pressed == true && this.inch_pressed == true
              && i >= 0 && i <= 15 ){
     // if this.inch == false, then this is the keystroke which is selecting
     // an inch
     if ( this.inch_pressed == false )
       this.inch_pressed = true;
     this.display.setText ( this.addSixteenth ( this.display.getText(), "" + i ) );
     // set flag so we don't allow any more input
     this.maxPressed = true;
   }

   if ( this.inch_pressed == true ) {
     this.enableSixteenths ( );
   }

   if ( this.initState ) {
     this.initState = false;
   }

 }

  /**
   *  start the program
   */
  public void init(){

   GridBagLayout gridbag = new GridBagLayout ( );
   GridBagConstraints constraints = new GridBagConstraints ( );
   setLayout ( gridbag );

   // display - spans 4 cells and one column
   buildConstraints ( constraints, 0, 0, 4, 1, 0, 12 );
   // stretches the component to fill both directions
   constraints.fill = GridBagConstraints.BOTH;
   this.display = new TextField( this.initOutput );
   gridbag.setConstraints( display, constraints );
   this.add ( display );

   CheckboxGroup group = new CheckboxGroup ( );

   buildConstraints ( constraints, 0, 1, 2, 1, 50, 12 );
   constraints.fill = GridBagConstraints.CENTER;
   this.dec_but = new Checkbox ( "DEC", group, false );
   gridbag.setConstraints( this.dec_but, constraints );
   this.dec_but.addItemListener( this );
   add ( this.dec_but);

   buildConstraints ( constraints, 2, 1, 2, 1, 50, 0 );
   constraints.fill = GridBagConstraints.CENTER;
   this.ft_in_but = new Checkbox ( "FT-IN", group, false );
   gridbag.setConstraints( this.ft_in_but, constraints );
   this.ft_in_but.addItemListener( this );
   add ( this.ft_in_but );

   this.ft_in_but.setState(true);

   // 13 button
   buildConstraints ( constraints, 0, 2, 1, 1, 25, 12 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_13 = new Button ( "13" );
   gridbag.setConstraints( b_13, constraints );
   this.b_13.addActionListener( this );
   this.b_13.setEnabled( false );
   this.b_13.setBackground( Color.white );
   add ( this.b_13 );

   // 14 button
   buildConstraints ( constraints, 1, 2, 1, 1, 25, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_14 = new Button ( "14" );
   gridbag.setConstraints( b_14, constraints );
   this.b_14.addActionListener( this );
   this.b_14.setEnabled( false );
   this.b_14.setBackground( Color.white );
   add ( b_14 );

   // 15 button
   buildConstraints ( constraints, 2, 2, 1, 1, 25, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_15 = new Button ( "15" );
   gridbag.setConstraints( b_15, constraints );
   this.b_15.addActionListener( this );
   this.b_15.setEnabled( false );
   this.b_15.setBackground( Color.white );
   add ( b_15 );

   // clear button
   buildConstraints ( constraints, 3, 2, 1, 1, 25, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_clr = new Button ( "Cl" );
   gridbag.setConstraints( this.b_clr, constraints );
   this.b_clr.addActionListener( this );
   this.b_clr.setBackground( Color.white );
   add ( this.b_clr );

   // 10 button
   buildConstraints ( constraints, 0, 3, 1, 1, 0, 12 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_10 = new Button ( "10" );
   gridbag.setConstraints( b_10, constraints );
   this.b_10.addActionListener( this );
   this.b_10.setEnabled( false );
   this.b_10.setBackground( Color.white );
   add ( b_10 );

   // 11 button
   buildConstraints ( constraints, 1, 3, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_11 = new Button ( "11" );
   gridbag.setConstraints( b_11, constraints );
   this.b_11.addActionListener( this );
   this.b_11.setEnabled( false );
   this.b_11.setBackground( Color.white );
   add ( b_11 );

   // 12 button
   buildConstraints ( constraints, 2, 3, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_12 = new Button ( "12" );
   gridbag.setConstraints( b_12, constraints );
   this.b_12.addActionListener( this );
   this.b_12.setEnabled( false );
   this.b_12.setBackground( Color.white );
   add ( b_12 );

   // divide button
   buildConstraints ( constraints, 3, 3, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_div = new Button ( " /" );
   gridbag.setConstraints( this.b_div, constraints );
   this.b_div.addActionListener( this );
   this.b_div.setBackground( Color.white );
   add ( this.b_div );

   // 7 button
   buildConstraints ( constraints, 0, 4, 1, 1, 0, 12 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_7 = new Button ( " 7" );
   gridbag.setConstraints( b_7, constraints );
   this.b_7.addActionListener( this );
   this.b_7.setBackground( Color.white );
   add ( b_7 );

   // 8 button
   buildConstraints ( constraints, 1, 4, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_8 = new Button ( " 8" );
   gridbag.setConstraints( b_8, constraints );
   this.b_8.addActionListener( this );
   this.b_8.setBackground( Color.white );
   add ( b_8 );

   // 9 button
   buildConstraints ( constraints, 2, 4, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_9 = new Button ( " 9" );
   gridbag.setConstraints( b_9, constraints );
   this.b_9.addActionListener( this );
   this.b_9.setBackground( Color.white );
   add ( b_9 );

   // mult button
   buildConstraints ( constraints, 3, 4, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_mul = new Button ( " *" );
   gridbag.setConstraints( this.b_mul, constraints );
   this.b_mul.addActionListener( this );
   this.b_mul.setBackground( Color.white );
   add ( this.b_mul );

   // 4 button
   buildConstraints ( constraints, 0, 5, 1, 1, 0, 12 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_4 = new Button ( " 4" );
   gridbag.setConstraints( b_4, constraints );
   this.b_4.addActionListener( this );
   this.b_4.setBackground( Color.white );
   add ( b_4 );

   // 5 button
   buildConstraints ( constraints, 1, 5, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_5 = new Button ( " 5" );
   gridbag.setConstraints( b_5, constraints );
   this.b_5.addActionListener( this );
   this.b_5.setBackground( Color.white );
   add ( b_5 );

   // 6 button
   buildConstraints ( constraints, 2, 5, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_6 = new Button ( " 6" );
   gridbag.setConstraints( b_6, constraints );
   this.b_6.addActionListener( this );
   this.b_6.setBackground( Color.white );
   add ( b_6 );

   // minus button
   buildConstraints ( constraints, 3, 5, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_sub = new Button ( " -" );
   this.b_sub.addActionListener( this );
   gridbag.setConstraints( this.b_sub, constraints );
   this.b_sub.setBackground( Color.white );
   add ( this.b_sub );

   // 1 button
   buildConstraints ( constraints, 0, 6, 1, 1, 0, 12 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_1 = new Button ( " 1" );
   this.b_1.addActionListener( this );
   gridbag.setConstraints( b_1, constraints );
   this.b_1.setBackground( Color.white );
   add ( b_1 );

   // 2 button
   buildConstraints ( constraints, 1, 6, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_2 = new Button ( " 2" );
   gridbag.setConstraints( b_2, constraints );
   this.b_2.addActionListener( this );
   this.b_2.setBackground( Color.white );
   add ( b_2 );

   // 3 button
   buildConstraints ( constraints, 2, 6, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_3 = new Button ( " 3" );
   gridbag.setConstraints( b_3, constraints );
   this.b_3.addActionListener( this );
   this.b_3.setBackground( Color.white );
   add ( b_3 );

   // add button
   buildConstraints ( constraints, 3, 6, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_add = new Button ( " +" );
   gridbag.setConstraints( this.b_add, constraints );
   this.b_add.addActionListener( this );
   this.b_add.setBackground( Color.white );
   add ( this.b_add );

   // 0 button
   buildConstraints ( constraints, 0, 7, 1, 1, 0, 12 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_0 = new Button ( " 0" );
   gridbag.setConstraints( b_0, constraints );
   this.b_0.addActionListener( this );
   this.b_0.setBackground( Color.white );
   add ( b_0 );

   // ft button
   buildConstraints ( constraints, 1, 7, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_ft = new Button ( " '" );
   gridbag.setConstraints( b_ft, constraints );
   this.b_ft.addActionListener( this );
   this.b_ft.setBackground( Color.white );
   add ( b_ft );

   // decimal button
   buildConstraints ( constraints, 2, 7, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_dec = new Button ( " ." );
   this.b_dec.addActionListener( this );
   gridbag.setConstraints( this.b_dec, constraints );
   this.b_dec.setEnabled( false );
   this.b_dec.setBackground( Color.white );
   add ( this.b_dec );

   // eq button
   buildConstraints ( constraints, 3, 7, 1, 1, 0, 0 );
   constraints.fill = GridBagConstraints.NONE;
   constraints.anchor = GridBagConstraints.CENTER;
   this.b_eq = new Button ( " =" );
   this.b_eq.addActionListener( this );
   gridbag.setConstraints( this.b_eq, constraints );
   this.b_eq.setBackground( Color.white );
   add ( this.b_eq );

   // change the fonts of the buttons from the default settings
   Font f = new Font ( "Courier", Font.BOLD, 14 );
   this.b_0.setFont( f );
   this.b_1.setFont( f );
   this.b_10.setFont( f );
   this.b_11.setFont( f );
   this.b_12.setFont( f );
   this.b_13.setFont( f );
   this.b_14.setFont( f );
   this.b_15.setFont( f );
   this.b_2.setFont( f );
   this.b_3.setFont( f );
   this.b_4.setFont( f );
   this.b_5.setFont( f );
   this.b_6.setFont( f );
   this.b_7.setFont( f );
   this.b_8.setFont( f );
   this.b_9.setFont( f );
   this.b_add.setFont( f );
   this.b_clr.setFont( f );
   this.b_div.setFont( f );
   this.b_eq.setFont( f );
   this.b_ft.setFont( f );
   this.b_dec.setFont( f );
   this.b_sub.setFont( f );
   this.b_mul.setFont( f );
   this.display.setText( this.getResult( ) );
   this.setBackground( Color.lightGray );

   this.clearButton();
  }

  /**
   * changes the operation of the calculator - Decimal or Ft-In-16th mode
   */
  public void itemStateChanged ( ItemEvent evt ) {
    Object source = evt.getSource();
    if ( source == this.ft_in_but ) {
      this.b_dec.setEnabled( false );
      this.b_ft.setEnabled( true );
      this.resetFlags();
      this.modeDecimal = false;
      this.display.setText( this.getResult() );
    }
    if ( source == this.dec_but ) {
      this.b_ft.setEnabled( false );
      this.b_dec.setEnabled( true );
      this.resetFlags();
      this.modeDecimal = true;
      this.display.setText( this.opBuffer1 + "" );
    }
  }

  /**
   * directs the flow of the program based on which key was pressed
   */
  public void actionPerformed ( ActionEvent event ) {
    Object src = event.getSource();

    // perform the operation of the key which was pressed
    if ( src == this.b_0 && this.maxPressed == false ){
      this.numericButton( 0 );
    }
    else if ( src == this.b_1 && this.maxPressed == false ) {
      this.numericButton( 1 );
    }
    else if ( src == this.b_2 && this.maxPressed == false ) {
      this.numericButton( 2 );
    }
    if ( src == this.b_3 && this.maxPressed == false ){
      this.numericButton( 3 );
    }
    else if ( src == this.b_4 && this.maxPressed == false ) {
      this.numericButton( 4 );
    }
    else if ( src == this.b_5 && this.maxPressed == false ) {
      this.numericButton( 5 );
    }
    if ( src == this.b_6 && this.maxPressed == false ){
      this.numericButton( 6 );
    }
    else if ( src == this.b_7 && this.maxPressed == false ) {
      this.numericButton( 7 );
    }
    else if ( src == this.b_8 && this.maxPressed == false ) {
      this.numericButton( 8 );
    }
    if ( src == this.b_9 && this.maxPressed == false ){
      this.numericButton( 9 );
    }
    else if ( src == this.b_10 && this.maxPressed == false ) {
      this.numericButton( 10 );
    }
    else if ( src == this.b_11 && this.maxPressed == false ) {
      this.numericButton( 11 );
    }
    if ( src == this.b_12 && this.maxPressed == false ){
      this.numericButton( 12 );
    }
    else if ( src == this.b_13 && this.maxPressed == false ) {
      this.numericButton( 13 );
    }
    else if ( src == this.b_14 && this.maxPressed == false ) {
      this.numericButton( 14 );
    }
    if ( src == this.b_15 && this.maxPressed == false ){
      this.numericButton( 15 );
    }
    if ( src == this.b_ft && this.maxPressed == false && this.operation == false
        && this.dec_but.getState() == false ){

      this.footButton( );
    }
    if ( src == this.b_clr ) {
      this.clearButton ( );
    }
    if ( src == this.b_add && this.operation == false ) {
      this.operation = true;
      this.addButton ( ) ;
    }
    if ( src == this.b_sub && this.operation == false ) {
      this.operation = true;
      this.subButton ( ) ;
    }
    if ( src == this.b_mul && this.operation == false ) {
      this.operation = true;
      this.mulButton ( ) ;
    }
    if ( src == this.b_eq && this.operation == false ) {
      this.operation = true;
      this.eqButton ( ) ;
    }
    if ( src == this.b_div && this.operation == false ) {
      this.operation = true;
      this.divButton ( ) ;
    }

    if ( src == this.b_dec ) {
      this.decButton ( );
    }
  }

  // **** queries *****

  /**
   * returns the last calculated result formatted for the ft-in-16th
   */
  public String getResult ( ) {
    if ( ! this.modeDecimal ) {
      return this.convertDoubleToOutputFormat( this.opBuffer1 );
    }
    else {
      return this.opBuffer1 + "";
    }
  }

  // **** commands *****

  /**
   * updates this calculators result using the specified value and operation
   */
  public void performOperation ( double value, int operation ) {
    // create a temp that holds the previous operation entered before the one
    // which called this method
    int op = this.operation1;

    // store the operation that called this method - we will execute that
    // operation next go round
    this.operation1 = operation;

   if ( op == this.ADD  ) {
      this.opBuffer1 = this.opBuffer1 + value;
    }
    else if ( op == this.SUB ) {
      this.opBuffer1 = this.opBuffer1 - value;
    }
    if ( op == this.MUL  ) {
       this.opBuffer1 = this.opBuffer1 * value;
    }
    if ( op == this.DIV  ) {
      if ( value != 0.0 )
       this.opBuffer1 = this.opBuffer1 / value;
      else {
              this.clearButton();
        this.display.setText("Div by 0 ERROR");
      }
    }
  }


  /**
   * returns the operator that is in the stack and puts the specified operator
   * on the stack
   */
  private int opStack ( int op ) {
    int lastOp = this.operation1;
    this.operation1 = op;
    return lastOp;
  }

  /**
   * returns a string formatted to the output of the calculator in
   * "Foot-inch-sixteenth mode from the specified double.
   */
  public String convertDoubleToOutputFormat ( double in ) {

    // local variables
    String out = "";            // a string to hold the formatted output
    int feet = 0;               // storage for the feet
    int inches = 0;             // storage for the inches
    int numerator = 0;          // storage for the sixteenths
    double temp = 0.0;            // temporary storage
    double round = 0.0;

    // cast to int - take the part before the decimal
    feet = (int)in;
    // subtract the buffer from the feet to get the decimal part
    temp = (in - feet) * 12.0;
    // get the inches
    inches = (int)temp;
    // get the sixteenths
    numerator = (int)( (temp - inches) * 16.0);
    // work on the rounding
    round = ( ( (temp - inches) * 16.0 ) - numerator);
    // round up a 16th
    if ( round > 0.5 ){
      numerator++;
    }
    //check if it caused the 16th's to roll over
    if ( numerator == 16 ){
      numerator = 0;
      inches++;
    }
    // check if it caused the inches to roll over
    if ( inches == 12 ){
      inches = 0;
      feet++;
    }
    // build the string
    out = this.addFoot( "" + feet );
    out = this.addInch( out, ("" + inches ) );
    if ( numerator != 0 ) {
      out = this.addSixteenth( out, ( numerator + "" ) );
    }

    // return the string
    return out;
  }

  /**
   * returns a double from the specified string ( this calculators display )
   */
  private double cvtDisplay ( String in ) {
    if ( this.modeDecimal ){
      Double d = new Double ( in );
      return d.doubleValue();
    }
    else
      return convertStringToFloat ( in );
  }

 /**
  * returns the double equivalent from the specified input string. Input string
  * shall be formatted to the output of the calculator ft-in-16th
  */
 public double convertStringToFloat ( String in ){

   int ftIndex = in.indexOf( '\'' );
   int dashIndex = in.indexOf( '-' );
   int spaceIndex = in.indexOf( ' ' );
   int slashIndex = in.indexOf( '/' );
   int inchIndex = in.indexOf( '\"' );

   int feet = 0;
   int inches = 0;
   int sixteenths = 0;
   int numerator = 0;
   int denominator = 0;

   // if foot mark exists - then we must break the string into parts

   // the foot mark exists
   if ( -1 != ftIndex ){
     String s = in.substring( 0, ftIndex );
     Integer f = new Integer ( in.substring( 0, ftIndex ) );
     feet = f.intValue();
   }

   // save the inches - if there are inches, both the dash and inch mark exist
   // first check if there are no sixteenths
   if ( -1 != inchIndex && -1 != dashIndex &&
        ( 2 >= ( ( inchIndex - 1 ) - ( dashIndex ) ) ) ) {
     // an int between the dash and inch marks - could be 1 or two chars
     Integer f = new Integer ( in.substring( dashIndex + 1, inchIndex ) );
     inches = f.intValue();
   }

   // save both the inches and sixteenths
   else if ( -1 != inchIndex && -1 != dashIndex ) {
     // an int between the dash and inch marks - could be 1 or two chars
     Integer f = new Integer ( in.substring( dashIndex + 1, spaceIndex ) );
     inches = f.intValue( );

     f = new Integer ( in.substring( spaceIndex + 1 ,slashIndex ) );
     numerator = f.intValue();

     f = new Integer ( in.substring( slashIndex+1, inchIndex ));
     denominator = f.intValue();
   }

   // the foot mark does not exist so just add feet
   else {
     Double d = new Double ( in );
     double d1 = d.doubleValue();
     feet = (int)d1;
   }

   float fraction = 0;
   if ( denominator != 0 ){
     fraction = ((float)numerator / (float)denominator);
   }
   float out = feet + ( ( inches  + ( fraction ) ) / 12 );
   return out;
  }

// **** Private methods ****

/**
 * reset the flags
 */
private void resetFlags ( ) {
  // set all of the flags to false
  this.ft_pressed = false;
  this.inch_pressed = false;
  this.sixTeenth_pressed = false;
  this.maxPressed = false;
  this.initState = true;
  this.decPressed = false;
  this.operation = false;
  this.b_10.setEnabled( false );
  this.b_11.setEnabled( false );
  this.b_12.setEnabled( false );
  this.b_13.setEnabled( false );
  this.b_14.setEnabled( false );
  this.b_15.setEnabled( false );
  }

  // borrowed from Sams "Teach yourself Java"
  // sets all of the constraints of the components
  // the first two arguments are: cell coordinates, gridx & gridy
  // the second two: gridwidth & gridheight (number of cells component spans)
  // the third two: weightx & weighty ( proportions of the rows and columns)
  private void buildConstraints ( GridBagConstraints gbc, int gx, int gy,
                                  int gw, int gh, int wx, int wy){
    gbc.gridx = gx;
    gbc.gridy = gy;
    gbc.gridwidth = gw;
    gbc.gridheight = gh;
    gbc.weightx = wx;
    gbc.weighty = wy;
  }

 /**
  * add Foot takes a input string and adds the foot symbol and dash for
  * the proper output
  */
 private String addFoot ( String ft ) {
   return ft + "'-";
 }

 /**
  * Concatenate the inch to the display in the proper ft-in-16th format
  */
 private String addInch ( String ft, String inch ) {
   return ft + inch + "\"";
 }

 /**
  * Concatenate the sixteenth on to the end of the display in the proper format
  */
 private String addSixteenth ( String in, String sixteenth ) {
   int len = in.length();
   in = in.substring( 0, len - 1 );
   // reduce 2/16, 6/16, 10/16, 14/16
   if ( sixteenth.equals( "2" ) ||  sixteenth.equals ( "6" ) ||
        sixteenth.equals( "10" ) ||  sixteenth.equals ( "14" ) ){
     int value = Integer.parseInt( sixteenth );
     value = value / 2;
     return in + " " + value + "/8\"";
   }
   // reduce 4/16, 12/16
   else if ( sixteenth.equals( "4" ) || sixteenth.equals( "12" ) ) {
     int value = Integer.parseInt( sixteenth );
     value = value / 4;
     return in + " " + value + "/4\"";
   }
   // reduce 1/2
   else if ( sixteenth.equals( "8" ) ) {
     int value = Integer.parseInt( sixteenth );
     value = value / 8;
     return in + " " + value + "/2\"";
   }
   // the remaining are all sixteenths and need no reducing
   else
     return in + " " + sixteenth + "/16\"";
 }

 /**
  * allow the 10 and eleven buttons to become active
  */
 private void enableFeet ( ){
   this.b_10.setEnabled( true );
   this.b_11.setEnabled( true );
 }

 /**
  * allow the 12, 13, 14, 15 buttons to become active
  */
 private void enableSixteenths ( ){
   this.b_12.setEnabled( true );
   this.b_13.setEnabled( true );
   this.b_14.setEnabled( true );
   this.b_15.setEnabled( true );
  }

 // constants
 private final String initOutput = "0";
 public final int INITIAL = 0;
 public final int ADD = 1;
 public final int SUB = 2;
 public final int MUL = 3;
 public final int DIV = 4;

// instance variables
 private double opBuffer1 = 0.0;              // the current total in the buffer
 private int operation1 = this.INITIAL;         // the last entered operation
 private boolean operation = false;         // an operation button was just pressed
 private boolean ft_pressed = false;        // the foot button has been pressed
 private boolean inch_pressed = false;      // the inch button has been pressed
 private boolean sixTeenth_pressed = false; // the sixteenth key has been pressed
 private boolean modeDecimal = false;       // the calculators mode is in decimal
 private boolean maxPressed = false;        // the max number of keys has been pressed
                                            // for ft-in-16th only
 private boolean initState = true;          // the calculator is in the initial state
 private boolean decPressed = false;        // the decimal button has been pressed

 // do we need - I think NOT
 Panel ptext = new Panel();
 Panel pbutton = new Panel();

 // the calculators display
 private TextField display;

// this calculators buttons
 private Button b_0;
 private Button b_1;
 private Button b_2;
 private Button b_3;
 private Button b_4;
 private Button b_5;
 private Button b_6;
 private Button b_7;
 private Button b_8;
 private Button b_9;
 private Button b_10;
 private Button b_11;
 private Button b_12;
 private Button b_13;
 private Button b_14;
 private Button b_15;
 private Button b_ft;
 private Button b_clr;
 private Button b_add;
 private Button b_sub;
 private Button b_div;
 private Button b_eq;
 private Button b_dec;
 private Button b_mul;

 // this calculators checkboxes
 private Checkbox dec_but;
 private Checkbox ft_in_but ;

} // end of class