// MSquare.java with magic square
  import java.awt.*;
  import java.applet.*;

  public class MSquare extends Applet {
     int b[]=new int[25];
     int size=5,cellht=35,cellwd=45;
     String name;

     public void init() {
         setLayout(new BorderLayout());
         canvas = new MSQCanvas();
         Panel p = new Panel();
         p.setLayout(new FlowLayout());
         button1=new Button("Generate");
         p.add(button1);
         add("North",canvas);
         add("South",p);
         name = getParameter("name");
         if (name == null)
             name = "Laura";

         name = "Hello " + name + "!";
         for(int i=1;i<=size;i++) {
           for(int j=1;j<=size;j++) {
             b[size*(i-1)+(j-1)]=0;
             b[size*(i-1)+(j-1)]=size*(i-1)+(j-1)+1;
           }
         }
         canvas.resize(300,300); 
         canvas.redraw(b,size,cellht,cellwd);
     }

        void button1_Clicked(Event event) {
         int n=0,h,k,lasth=0,lastk=0;
         h= (int)(size*Math.random()+1);
         k= (int)(size*Math.random()+1);
         int iincr, jincr;
         iincr= -1+2*((int)(2*Math.random()));
         jincr= -1+2*((int)(2*Math.random()));
         double sw;  

         sw=Math.random();
         for(int i=1;i<=size;i++) {
           for(int j=1;j<=size;j++) {
             n=n+1;
             b[size*(k-1)+(h-1)]=n;
             lasth=h;lastk=k;
             h=h+iincr;if (h<1) h=size;else if(h>size) h=1;  
             k=k+jincr;if (k>size) k=1;else if(k<1) k=size;
           }
           h=lasth;k=lastk;
           if(sw<0.5) {   
             h=h-iincr;if (h<1) h=size;else if(h>size) h=1; 
           } else { 
             k=k-jincr;if (k<1) k=size;else if(k>size) k=1; 
           } 
         } 
         canvas.redraw(b,size,cellht,cellwd);
        }

        public boolean handleEvent(Event event) {
                if (event.target == button1 && event.id == Event.ACTION_EVENT) {
                        button1_Clicked(event);
                }
                return super.handleEvent(event);
        }
     Button button1;
     private MSQCanvas canvas;
 }
class MSQCanvas extends Canvas {
     private int[] b;
     private int size,cellht,cellwd;
     public void redraw(int v[], int s, int h, int w) { 
       b=v;
       size=s;
       cellht=h;
       cellwd=w;
       repaint();
     }
     public void paint(Graphics g) {
         Font f = new Font("CourierNew", Font.BOLD, 20);
         g.setFont(f);
         g.setColor(Color.red);
         for (int i=0;i<=size;i++) {
           g.drawLine(5,5+cellht*i,size*(cellwd+1),5+cellht*i);
           }
         for (int i=0;i<=size;i++) {
           g.drawLine(5+cellwd*i,5,5+cellwd*i,size*(cellht+1));
           }
         for (int i=1;i<=size;i++) {
           for (int j=1;j<=size;j++) {
             g.drawString(Integer.toString(b[size*(i-1)+(j-1)]),
               5+cellwd*(i-1),5+cellht*j-10);
             }
           } 
     }
}