/*
   Copyright F. P. Marin ( July 22 18:11:20 1998 )
   E-mail: felix@bloch.ciens.ucv.ve
   
   Permission to use, copy, modify and distribute this software and its
   documentation for NON-COMERCIAL purposes and without fee is hereby
   granted provided that this copyright notice appears in all copies.

   F. P. Marin makes no representations or warranties about the suitability
   of the software, either express or implied, including but no limited to
   the implied warranties of merchantability, fitness for a particular
   purpose, or non-infringement. F. P. Marin shall not be liable for any
   damage suffered by license as a result of using, modifying or
   distributing this software or its derivatives.
 
   Html code:

   <applet archive="Gcd.jar"
              code="Gcd.class"
            height=100
             width=300>
   </applet>
*/
import java.awt.*;


public class Gcd extends java.applet.Applet
{      
       Button b=new Button("Gcd = ");
       Label l[]=new Label[2];
       TextField tf[]=new TextField[3];


       public void init()
       {
        setLayout(new GridLayout(3,2));
        l[0]=new Label("A number = ",Label.RIGHT);
        l[1]=new Label("Another number = ",Label.RIGHT);
        tf[0]=new TextField(20);
        tf[1]=new TextField(20);
        tf[2]=new TextField(20);
        add(l[0]);
        add(tf[0]);
        add(l[1]);
        add(tf[1]);
        add(b);
        add(tf[2]);
       }


       // action implements the Euclides algorithm
       //
       public boolean action(Event e,Object arg)
       {
        if ( e.target!=b ) return true;
        tf[2].setText("");
        long u=0L;
        try {
             u=Long.parseLong(tf[0].getText());
        } catch ( NumberFormatException nfe ) {
             tf[0].setText("");
        }
        long v=0L;
        try {
             v=Long.parseLong(tf[1].getText());
        } catch ( NumberFormatException nfe ) {
             tf[1].setText("");
        }
        u=Math.abs(u);
        v=Math.abs(v);
               if ( v!=0L ) {
                  for ( long temp ; (u%=v)!=0L ; ) {
                      temp=u;
                      u=v;
                      v=temp;
                  }
                  tf[2].setText(v + "");
        } else if ( u!=0L ) {
                  tf[1].setText("0");
                  tf[2].setText(u + "");
                  
        } else {
                  tf[0].setText("");
                  tf[1].setText("");
        }
        return true;
       }
}