/////////////// Purpose.  C++ application that uses Java GUI \\\\\\\\\\\\\\\\

#include <iostream.h>
#include <stdlib.h>
#include <time.h>
#include "GridGameAdapter.cpp"

class GridGameClass {
private:
   int x;
   int y;
   GridGameAdapter board;
public:
   GridGameClass( int size ) : board(size) {
      time_t   t;
      srand((unsigned) time(&t));
      x = rand() % size;
      y = rand() % size;
   }
   void guess( int a, int b ) {
      int xx = a - x;
      if (xx < 0) xx *= -1;
      int yy = b - y;
      if (yy < 0) yy *= -1;
      board.update( a, b, xx+yy );
   }
};

void main( void ) {
   int x, y;
   cout << "Enter size: ";
   cin >> x;
   GridGameClass gg( x );
   while (1) {
      cout << "Enter x y: ";
      cin >> x >> y;
      gg.guess( x, y );
   }
}

//////// Purpose.  C++ adapter between C++ application and Java GUI \\\\\\\\\

#include <jni.h>

class GridGameAdapter {
private:
   JavaVM*    jvm;
   JNIEnv*    env;
   jobject    obj;
   jmethodID  upda;
public:
   GridGameAdapter( int size ) {
      JavaVMOption options[2];
      options[0].optionString = "-Djava.compiler=NONE";
      options[1].optionString = "-Djava.class.path=c:\\msdev\\projects\\cpp";
      // options[2].optionString = "-verbose:jni";

      JavaVMInitArgs vm_args;
      vm_args.version            = JNI_VERSION_1_2;
      vm_args.options            = options;
      vm_args.nOptions           = 2;
      vm_args.ignoreUnrecognized = true;

      int res = JNI_CreateJavaVM( &jvm, (void**)&env, &vm_args );
      if (res < 0) cout << "create failed" << endl;

      jclass    clas = env->FindClass( "GridGameJavaGUI" );
      jmethodID ctor = env->GetMethodID( clas, "<init>", "(I)V" );
      obj  = env->NewObject( clas, ctor, size );
      upda = env->GetMethodID( clas, "update", "(III)V" );
   }
   void update( int x, int y, int sc ) {
      env->CallVoidMethod( obj, upda, x, y, sc );
   }
   ~GridGameAdapter() {
      jvm->DestroyJavaVM();
   }
};

///////// Purpose.  Java GUI component for C++ GridGame application \\\\\\\\\

import java.awt.*;
import java.awt.event.*;

public class GridGameJavaGUI {
   private Label[][] labels;
   private Font font;
   public GridGameJavaGUI( int size ) {
      labels = new Label[size][size];
      Frame frame = new Frame( "GridGameBoard" );
      frame.addWindowListener( new WindowAdapter() {
         public void windowClosing( WindowEvent e ) { System.exit( 0 ); } } );
      frame.setLayout( new GridLayout(size,size) );
      for (int i=0; i < size; i++)
         for (int j=0; j < size; j++) {
            labels[i][j] = new Label(Integer.toString(i) +" " +j, Label.CENTER);
            frame.add( labels[i][j] );
         }
      font = new Font( "Helvetica", Font.BOLD, 16 );
      frame.pack();
      frame.setVisible( true );
   }
   public void update( int x, int y, int score ) {
      labels[x][y].setBackground( Color.yellow );
      labels[x][y].setForeground( Color.red );
      labels[x][y].setFont( font );
      labels[x][y].setText( Integer.toString( score ) );
   }
}