//pp0.java
class pp0 {
}

//pp1.java
class pp1 {
     public static void main( ){
         System.out.println("Hey, PI=" + Math.PI);
     }
} // pp1  ---  why error ?


//pp2.java  -- note the parameter of main
class pp2 {
     public static void main(String x[ ] ){
         System.out.println("Hey, PI=" + Math.PI);
     }
}


//pp3.java
class pp3 {
     public static void main(String x[ ] ){
         //System.out.println("Hey, PI=" + Math.PI);
         for(i=1; i<=9; ++i) {
                 for(k=1; k<=9; k++) print("" + i*k);
             print("\n");   /* 用起來比較清爽 */ 
         }
     }
     void print(String x) { System.out.print(x); }
}  // pp3 --- why the print( ) function error? 




//pp4.java
// -- note that main() is static, and thus can only use static fn
class pp4 {
     public static void main(String x[ ] ){
         //System.out.println("Hey, PI=" + Math.PI);
         for(int i=1; i<=9; ++i) {
                 for(int k=1; k<=9; k++){
                    if(i*k < 10) print(" ");
                    print("  " + i*k);
                 }
             print("\n");
         }
     }
     static void print(String x) { System.out.print(x); }
}



//pp5.java
class pp5 {
     public static void main(String x[ ] ){
          new pp5( );
     }
     pp5 ( ) {   // we can use non-static functions in here
         myfun( );
     }
     void myfun( ) {
         //System.out.println("Hey, PI=" + Math.PI);
         for(int i=1; i<=9; ++i) {
                 for(int k=1; k<=9; k++){
                    if(i*k < 10) print(" ");
                    print("  " + i*k);
                 }
             print("\n");
         }
     }
     void print(String x) { System.out.print(x); }
}



//pp6.java
import java.awt.*;
class pp6 {
     Frame f = new Frame("Ha Ha Ha");
     public static void main(String x[ ] ){
          new pp6( );
     }
     pp6 ( ) {
         myfun( );
     }
     void myfun( ) {
          f.setVisible(true);    //f.show( );
     }
     void print(String x) { System.out.print(x); }
}







//pp7.java
import java.awt.event.*;
import java.awt.*;
class pp7 extends WindowAdapter {
     Frame f = new Frame("Ha Ha Ha");
     public static void main(String x[ ] ){
          new pp7( );
     }
     pp7 ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
     }
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
     void print(String x) { System.out.print(x); }
}




//pp8.java
// do NOT forget to setVisible ! 
// use the WindowAdapter 
import java.awt.event.*;
import java.awt.*;
class pp8 extends WindowAdapter {
     Frame f = new Frame("Ha Ha Ha");
     public static void main(String x[ ] ){
          new pp8( );
     }
     pp8 ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          f.addWindowListener(this);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
     }
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
     void print(String x) { System.out.print(x); }
}



//pp9.java
// using the event handler in other class
import java.awt.event.*;
import java.awt.*;
class pp9  {
     Frame f = new Frame("Ha Ha Ha");
     public static void main(String x[ ] ){
          new pp9( );
     }
     pp9 ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau(f);   // arbu is a YLau
          f.addWindowListener(arbu);     // !!! important 
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
     }
     void print(String x) { System.out.print(x); }
} // pp9
///////// YLau is an independent class 
class YLau extends WindowAdapter {
     Frame fff;
     YLau(Frame x) {
          fff = x;
     }
     public void windowClosing(WindowEvent e){
         fff.dispose( );
     }
}





//ppa.java
// note that YLau is an inner class
import java.awt.event.*;
import java.awt.*;
class ppa  {
     Frame f = new Frame("Ha Ha Ha");
     public static void main(String x[ ] ){
          new ppa( );
     }
     ppa ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau( );
          f.addWindowListener(arbu);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
     }
     void print(String x) { System.out.print(x); }
//// not end yet
class YLau extends WindowAdapter {
     //
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
}
}  // ppa











//ppb.java
// why ? why can NOT see the button ba ?  bb? bc?
import java.awt.event.*;
import java.awt.*;
class ppb  {
     Frame f = new Frame("Ha Ha Ha");
     Button ba, bb, bc;
     public static void main(String x[ ] ){
          new ppb( );
     }
     ppb ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau( );
          f.addWindowListener(arbu);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
          ba = new Button("AAAA");
          bb = new Button("BBBBB");
          bc = new Button("CCC");
          bb.setForeground(Color.blue);
          bb.setBackground(new Color(28, 228, 58));
          f.add("West", ba);   // add ba into f 
    }
     void print(String x) { System.out.print(x); }
//// not end yet
class YLau extends WindowAdapter {
     //
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
}
} // ppb


//ppc.java
// do NOT forget to validate !
import java.awt.event.*;
import java.awt.*;
class ppc  {
     Frame f = new Frame("Ha Ha Ha");
     Button ba, bb, bc;
     public static void main(String x[ ] ){
          new ppc( );
     }
     ppc ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau( );
          f.addWindowListener(arbu);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
          ba = new Button("AAAA");
          bb = new Button("BBBBB");
          bc = new Button("CCC");
          bb.setForeground(Color.blue);
          bb.setBackground(new Color(28, 228, 58));
          f.add("West", ba);  //  add ba into f
          f.validate( );   // !! important  
    }
     void print(String x) { System.out.print(x); }
//// not end yet
class YLau extends WindowAdapter {
     //
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
}
}

//ppd.java
import java.awt.event.*;
import java.awt.*;
class ppd  {
     Frame f = new Frame("Ha Ha Ha");
     Button ba, bb, bc;
     public static void main(String x[ ] ){
          new ppd( );
     }
     ppd ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau( );
          f.addWindowListener(arbu);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
          ba = new Button("AAAA");
          bb = new Button("BBBBB");
          bc = new Button("CCC");
          bb.setForeground(Color.blue);
          bb.setBackground(new Color(28, 228, 58));
          Panel p=new Panel();
          p.add(ba); p.add(bb);
          f.add("West", p);
          f.add(bc, "Center");
          f.add(new Button("eeee"), BorderLayout.EAST);
          f.validate( );   // important !
    }
     void print(String x) { System.out.print(x); }
//// not end yet
class YLau extends WindowAdapter {
     //
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
}
}


//ppe.java
import java.awt.event.*;
import java.awt.*;
class ppe  {
     Frame f = new Frame("Ha Ha Ha");
     Button ba, bb, bc;
     public static void main(String x[ ] ){
          new ppe( );
     }
     ppe ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau( );
          f.addWindowListener(arbu);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
          ba = new Button("Quit");
          bb = new Button("BBBBB");
          bc = new Button("CCC");
          bb.setForeground(Color.blue);
          bb.setBackground(new Color(28, 228, 58));
          Panel p=new Panel();
          p.add(ba); p.add(bb);
          f.add("West", p);
          f.add(bc, "Center");
          f.add(new Button("eeee"), BorderLayout.EAST);
          ba.addActionListener(new BenLau() );    
          bb.addActionListener(new BenLau() );    
          f.validate( ); 
    }


     void print(String x) { System.out.print(x); }
//// not end yet
class YLau extends WindowAdapter {
     //
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
}
class BenLau implements ActionListener {
    public void actionPerformed(ActionEvent e){
        System.exit(0);
    }
} /// /// ///
} // end of ppe.java

//ppf.java
import java.awt.event.*;
import java.awt.*;
class ppf  {
     Frame f = new Frame("Ha Ha Ha");
     Button ba, bb, bc;
     public static void main(String x[ ] ){
          new ppf( );
     }
     ppf ( ) {
         print("Hey .. Running ...\n");
         myfun( );
     }
     void myfun( ) {
          YLau arbu = new YLau( );
          f.addWindowListener(arbu);
          f.setSize(580,380);
          f.setVisible(true);    //f.show( );
          ba = new Button("Quit");
          bb = new Button("BBBBB");
          bc = new Button("CCC");
          bb.setForeground(Color.blue);
          bb.setBackground(new Color(28, 228, 58));
          Panel p=new Panel(new BorderLayout());
          p.add(ba, "North"); p.add("Center", bb);
          bx = new Button("----");  // see the end of this program
          p.add(bx, "South");
          Panel p2 = new Panel(new BorderLayout());
          p2.add(p, "North");
          bx.setForeground(Color.red);
          bx.setBackground(new Color(58, 198, 238));
          bx.setLabel("< bx >");    // change caption
          BenLau chang3 = new BenLau( );
          bb.addActionListener( chang3 );    
          bx.addActionListener( chang3 );    
          f.add("West", p2);
          f.add(bc, "Center");
          f.add(new Button("eeee"), BorderLayout.EAST);
          ba.addActionListener(new BenLau() );    
          f.validate( ); 
    }
     void print(String x) { System.out.print(x); }
//// not end yet
class YLau extends WindowAdapter {
     //
     public void windowClosing(WindowEvent e){
         f.dispose( );
     }
}
class BenLau implements ActionListener {
    public void actionPerformed(ActionEvent e){
        Object who = e.getSource();
        if(who == ba) System.exit(0);
        if(who == bb) bc.setBackground(Color.green);
        if(who == bx) bc.setBackground(Color.blue);
    }
}
     Button bx;   ////////////////    Note: this is global !
} // ppf ends here