/**
 * Homework:  Assignment 3
 * Exercise:  6.3 in textbook, page 342
 * Author:    Richard Parry
 * Date:      July 12, 1998
 * Filename:  RationalTest.java
 * School:    UCSD, Summer 98 Java 1 class
 * 
 * Description:
 * This program, <CODE><B>RationalTest</B><CODE> tests the funtionality 
 * of the Rational Class.  It provides the front end GUI for the
 * underlying program (Rational.java).
 **/

import java.applet.Applet;
import java.awt.*;    // import the java.awt package
import java.awt.event.*;  // import the java.awt.event package
import java.text.DecimalFormat; // required for formatting percent

// declare class
public class RationalTest extends Applet implements ActionListener {

  // variables
  Label prompt1, prompt2, prompt3, prompt4;
  TextField input1, input2, input3, input4;
  float floatResult;
  Button compute;
  private Rational r1;
  private Rational r2;


  public void init() {
    
    /** Instantiate objects r1 and r2. When an object is instantiated,
     * the Rational constructor is called automatically to set private instance
     * variables to their default values.
     */
    r1 = new Rational();
    r2 = new Rational();

    // declare prompts
    prompt1 = new Label( "Numerator 1" );
    prompt2 = new Label( "Denominator 1" );
    prompt3 = new Label( "Numerator 2" );
    prompt4 = new Label( "Denominator 2" );

    // declare input fields, note field that is tied to event
    input1 = new TextField( 10 );
    input2 = new TextField( 10 );
    input3 = new TextField( 10 );
    input4 = new TextField( 10 );

    // add to GUI
    add( prompt1 );
    add( input1 );
    add( prompt3 );
    add( input3 );
    add( prompt2 );
    add( input2 );
    add( prompt4 );
    add( input4 );

    // init button
    compute = new Button( "Compute" );
    compute.addActionListener( this );
    add( compute );

  } // end init method
  
  
  
  // display the results
  public void paint( Graphics g ) {

    // declare decimal precision format
    DecimalFormat precision2 = new DecimalFormat( "#.00" );

    // display banner
    g.drawString( "RATIONAL - Fractional Arithmetic", 100, 110 );
    g.drawString( "- RESULTS -", 160, 150 );
    int xPosition = 90;
    int yPosition = 165;

    // Add two rational numbers by calling add method
    Rational addResult = Rational.add( r1, r2);
    floatResult = Rational.rational2Decimal(addResult); // convert to decimal
    g.drawString("Addition " + r1.toString() + " + " + r2.toString() +
		 " = " + addResult.toString() +
		 "  ~ " + precision2.format( floatResult ),
		 xPosition, yPosition);
    yPosition += 15; // move cursor to next line


    // Substract two rational numbers by calling sub method
    Rational subResult = Rational.sub( r1, r2);
    floatResult = Rational.rational2Decimal(subResult); // convert to decimal
    g.drawString("Substract " + r1.toString() + " - " + r2.toString() +
		 " = " + subResult.toString() +
		 "  ~ " + precision2.format( floatResult ),
		 xPosition, yPosition);
    yPosition += 15; // move cursor to next line


    // Multiply two rational numbers by calling mul method
    Rational mulResult = Rational.mul( r1, r2);
    floatResult = Rational.rational2Decimal(mulResult); // convert to decimal
    g.drawString("Multiply " + r1.toString() + " * " + r2.toString() +
		 " = " + mulResult.toString() +
		 "  ~ " + precision2.format( floatResult ),
		 xPosition, yPosition);
    yPosition += 15; // move cursor to next line


    // Divide two rational numbers by calling div method
    Rational divResult = Rational.div( r1, r2);
    floatResult = Rational.rational2Decimal(divResult); // convert to decimal
    g.drawString("Divide " + r1.toString() + " / " + r2.toString() +
		 " = " + divResult.toString() +
		 "  ~ " + precision2.format( floatResult ),
		 xPosition, yPosition);
    yPosition += 15; // move cursor to next line

  } // end paint method
  

  // process user's actions
  public void actionPerformed( ActionEvent e ) {
    int numerator1, denominator1, numerator2, denominator2;
    numerator1 = Integer.parseInt( input1.getText() );
    denominator1 = Integer.parseInt( input2.getText() );
    numerator2 = Integer.parseInt( input3.getText() );
    denominator2 = Integer.parseInt( input4.getText() );

    // create two objects to represent two rational numbers
    r1 = new Rational(numerator1, denominator1);
    r2 = new Rational(numerator2, denominator2);

    repaint();
  }

} // end class declaration