Connect4.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Connect4 {

    /**
    *   Program:    Connect4.java
    *   Purpose:    Stacking disk game for 2 players
    *   Creator:    Chris Clarke
    *   Created:    19.08.2007
    *   Modified:   29.11.2012 (JFrame)
    */

    public static void main(String[] args) {
        Connect4JFrame frame = new Connect4JFrame();
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

class Connect4JFrame extends JFrame implements ActionListener {

    private Button      btn1, btn2, btn3, btn4, btn5, btn6, btn7;
    private Label       lblSpacer;
    MenuItem        newMI, exitMI, redMI, yellowMI;
    int[][]         theArray;
    boolean         end=false;
    boolean         gameStart;
    public static final int BLANK = 0;
    public static final int RED = 1;
    public static final int YELLOW = 2;

    public static final int MAXROW = 6; // 6 rows
    public static final int MAXCOL = 7; // 7 columns

    public static final String SPACE = "                  "; // 18 spaces

    int activeColour = RED;

    public Connect4JFrame() {
        setTitle("Connect4 by Chris Clarke");
        MenuBar mbar = new MenuBar();
        Menu fileMenu = new Menu("File");
        newMI = new MenuItem("New");
        newMI.addActionListener(this);
        fileMenu.add(newMI);
        exitMI = new MenuItem("Exit");
        exitMI.addActionListener(this);
        fileMenu.add(exitMI);
        mbar.add(fileMenu);
        Menu optMenu = new Menu("Options");
        redMI = new MenuItem("Red starts");
        redMI.addActionListener(this);
        optMenu.add(redMI);
        yellowMI = new MenuItem("Yellow starts");
        yellowMI.addActionListener(this);
        optMenu.add(yellowMI);
        mbar.add(optMenu);
        setMenuBar(mbar);

        // Build control panel.
        Panel panel = new Panel();

        btn1 = new Button("1");
        btn1.addActionListener(this);
        panel.add(btn1);
        lblSpacer = new Label(SPACE);
        panel.add(lblSpacer);

        btn2 = new Button("2");
        btn2.addActionListener(this);
        panel.add(btn2);
        lblSpacer = new Label(SPACE);
        panel.add(lblSpacer);

        btn3 = new Button("3");
        btn3.addActionListener(this);
        panel.add(btn3);
        lblSpacer = new Label(SPACE);
        panel.add(lblSpacer);

        btn4 = new Button("4");
        btn4.addActionListener(this);
        panel.add(btn4);
        lblSpacer = new Label(SPACE);
        panel.add(lblSpacer);

        btn5 = new Button("5");
        btn5.addActionListener(this);
        panel.add(btn5);
        lblSpacer = new Label(SPACE);
        panel.add(lblSpacer);

        btn6 = new Button("6");
        btn6.addActionListener(this);
        panel.add(btn6);
        lblSpacer = new Label(SPACE);
        panel.add(lblSpacer);

        btn7 = new Button("7");
        btn7.addActionListener(this);
        panel.add(btn7);

        add(panel, BorderLayout.NORTH);
        initialize();
        // Set to a reasonable size.
        setSize(1024, 768);
    } // Connect4

    public void initialize() {
        theArray=new int[MAXROW][MAXCOL];
        for (int row=0; row<MAXROW; row++)
            for (int col=0; col<MAXCOL; col++)
                theArray[row][col]=BLANK;
        gameStart=false;
    } // initialize

    public void paint(Graphics g) {
        g.setColor(Color.BLUE);
        g.fillRect(110, 50, 100+100*MAXCOL, 100+100*MAXROW);
        for (int row=0; row<MAXROW; row++)
            for (int col=0; col<MAXCOL; col++) {
                if (theArray[row][col]==BLANK) g.setColor(Color.WHITE);
                if (theArray[row][col]==RED) g.setColor(Color.RED);
                if (theArray[row][col]==YELLOW) g.setColor(Color.YELLOW);
                g.fillOval(160+100*col, 100+100*row, 100, 100);
            }
        check4(g);
    } // paint

    public void putDisk(int n) {
    // put a disk on top of column n
        // if game is won, do nothing
        if (end) return;
        gameStart=true;
        int row;
        n--;
        for (row=0; row<MAXROW; row++)
            if (theArray[row][n]>0) break;
        if (row>0) {
            theArray[--row][n]=activeColour;
            if (activeColour==RED)
                activeColour=YELLOW;
            else
                activeColour=RED;
            repaint();
        }
    }

    public void displayWinner(Graphics g, int n) {
        g.setColor(Color.BLACK);
        g.setFont(new Font("Courier", Font.BOLD, 100));
        if (n==RED)
            g.drawString("Red wins!", 100, 400);
        else
            g.drawString("Yellow wins!", 100, 400);
        end=true;
    }

    public void check4(Graphics g) {
    // see if there are 4 disks in a row: horizontal, vertical or diagonal
        // horizontal rows
        for (int row=0; row<MAXROW; row++) {
            for (int col=0; col<MAXCOL-3; col++) {
                int curr = theArray[row][col];
                if (curr>0
                 && curr == theArray[row][col+1]
                 && curr == theArray[row][col+2]
                 && curr == theArray[row][col+3]) {
                    displayWinner(g, theArray[row][col]);
                }
            }
        }
        // vertical columns
        for (int col=0; col<MAXCOL; col++) {
            for (int row=0; row<MAXROW-3; row++) {
                int curr = theArray[row][col];
                if (curr>0
                 && curr == theArray[row+1][col]
                 && curr == theArray[row+2][col]
                 && curr == theArray[row+3][col])
                    displayWinner(g, theArray[row][col]);
            }
        }
        // diagonal lower left to upper right
        for (int row=0; row<MAXROW-3; row++) {
            for (int col=0; col<MAXCOL-3; col++) {
                int curr = theArray[row][col];
                if (curr>0
                 && curr == theArray[row+1][col+1]
                 && curr == theArray[row+2][col+2]
                 && curr == theArray[row+3][col+3])
                    displayWinner(g, theArray[row][col]);
            }
        }
        // diagonal upper left to lower right
        for (int row=MAXROW-1; row>=3; row--) {
            for (int col=0; col<MAXCOL-3; col++) {
                int curr = theArray[row][col];
                if (curr>0
                 && curr == theArray[row-1][col+1]
                 && curr == theArray[row-2][col+2]
                 && curr == theArray[row-3][col+3])
                    displayWinner(g, theArray[row][col]);
            }
        }
    } // end check4

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == btn1)
            putDisk(1);
        else if (e.getSource() == btn2)
            putDisk(2);
        else if (e.getSource() == btn3)
            putDisk(3);
        else if (e.getSource() == btn4)
            putDisk(4);
        else if (e.getSource() == btn5)
            putDisk(5);
        else if (e.getSource() == btn6)
            putDisk(6);
        else if (e.getSource() == btn7)
            putDisk(7);
        else if (e.getSource() == newMI) {
            end=false;
            initialize();
            repaint();
        } else if (e.getSource() == exitMI) {
            System.exit(0);
        } else if (e.getSource() == redMI) {
            // don't change colour to play in middle of game
            if (!gameStart) activeColour=RED;
        } else if (e.getSource() == yellowMI) {
            if (!gameStart) activeColour=YELLOW;
        }
    } // end ActionPerformed

} // class